Recently I installed Ruined-Tail's Tale, and have been playing it just fine. He'd travel with me, talk with me, help me with fights, etc. I finished the Legacy Lost quest with the Jemane Brothers, got them to Weatherleah, and when I slept at their ruined house, Ruin ran off and left his journal. Went outside, saved the game, then quit. My game has been quite stable up to this point.
During this time, I updated some of the BAIN packages with esps that had been cleaned with TES4Edit (they had been cleaned before then, I just updated the 7z/zips with them so they'd stop showing as having conflicts in Wrye Bash). I also installed OBMM, along with the Detailed Terrain packages.
Eventually, I restarted Oblivion, and started running towards the Imperial City. When I got a bit past the fort in the road, I met up with a Spriggan who summoned a bear, followed by the game crashing. Reloaded, ran towards the IC again, and this time made an extra save just before passing through the fort. Continued on, and the Spriggan was replaced by a deer, and I didn't have any problems in that area. Got up to the point where the Wawnet Inn and the burned-down remains of the other (mod-added) Inn would come into view, and promptly got another crash.
Now, when I reloaded the save from just before the fort, I literally could not go more than 5 steps without a crash. I tried it multiple times and it would keep crashing if I moved too far (it didn't seem to crash if I remained still). Then I tried to fast travel to the Wawnet Inn, and got there just fine. Ran onto the IC bridge, and prompty got a crash.
At this point, I thought it might be some obscure issue with Detailed Terrain, since that was the only thing I added before the crashes started, so I uninstalled it. Loaded up a save (I think the autosave from the fast-travel attempt, or farther back when I exited Weatherleah), and ran towards the IC again. Got to where the Inns would come into view, another crash. Following this, I decided to fast travel directly to the Arena. Got there fine, and I could move about the area fine. Next, I fast-traveled to Cheydinhal (don't remember if it was just outside the city, or just inside the west gate). Inside, I made a save and headed to that island in the middle of the river. As I got into the wooden bridge, I got another crash.
Around now, I thought it might be an issue with the Companion Compatibility mod, so I re-enabled Detailed Terrain, and disabled CC. Restarted from the last save again, found the guy I needed to tell me where Ruin is, and ran out to his camp with no issue. Saved, talked to Ruin, and just as the conversation ended, another crash. Re-enabled CC, reloaded the last save, talked with Ruin just fine, and beat the assassins. Talked to Ruin again, found the note, and brought it back to him. Afterward, ran into a large group of bandits just by the road... like, 6 or 7 of them, all coming at me. Given my current state, there was no way I could deal with that much at once, so after a couple had been properly killed, I had to cheat a little and console-kill the rest. At this point, I repaired my and Ruin's equipment, recharged our enchanted weapons, then made a save and quit playing for the night. Given the length of time it played that time, I was hoping the crashes cleared themselves up... thought it may have just been an issue with that portion of Ruined-Tail's quest, since that's when it all started.
Picked the game up again today, went to the Orc's shop and sold the loot. Went over to the Mages' Guild to get some health potions and ingredients. Made some potions, then headed out, going towards Faregyl. Ran into some wolves along the Blue Road, and dispatched them with no trouble. Got all the way out where the road meets the Red Ring Road, again, no problems. Was thinking that maybe it was actually cleared up, given how long it's been. Headed south, and after a little bit... crash. Reloaded the last save (which thankfully wasn't too far back), headed south again, and it again crashed when I reached the same area.
Another reload, and this time I tried to fast travel to Fort Magia, which was along the path I was headed. Got there and came face-to-face with a Minotaur Lord. Me and Ruin took care of it, then continued south. Got to where the burned-down alchemy shop was and "slept" there for the night (technically waited). Left the area, and as I was getting near the magicka well, another crash.
At that point, I just got fed up. It's very difficult to keep playing with as often as it's crashing. So, I decided to come here, describe what's been going on, and hope to get some insight into the possible causes for the crashes so that I may fix it. My load order is:
Spoiler
00 Oblivion.esm
01 All Natural Base.esm [Version 1.3]
02 Oscuro's_Oblivion_Overhaul.esm [Version 1.34]
03 Kvatch Rebuilt.esm
04 Oblivifall Master File.esm [Version 1.0]
05 Unofficial Oblivion Patch.esp [Version 3.3.5]
06 DLCShiveringIsles.esp
07 Unofficial Shivering Isles Patch.esp [Version 1.4.2]
08 All Natural.esp [Version 1.3]
09 All Natural - SI.esp [Version 1.3]
0A Side's EAX Control.esp [Version 1.0]
0B All Natural - Real Lights.esp [Version 1.3]
0C Dynamic Map.esp [Version 2.0]
++ MaleBodyReplacerV3.esp
0D Oscuro's_Oblivion_Overhaul.esp [Version 1.34]
0E Zombie Diversity.esp
0F Skeleton Diversity.esp
10 Oblivifall - Something's Not Right.esp [Version 1.0]
11 Kragenir's Death Quest.esp
12 KDQ - Rural Line Additions.esp
13 Kvatch Rebuilt.esp
++ Kvatch Rebuilt - OOO Compatibility.esp
14 Kvatch Rebuilt Weather Patch.esp
15 Cyrodiil Travel Services.esp [Version 2.0.7]
16 RTT.esp
17 MannimarcoRevisited.esp
18 MannimarcoRevisitedOOO.esp [Version 0.1]
19 Faregyl.esp [Version 2.0.2]
1A Molapi.esp [Version 1.0.1]
1B PTMudwater.esp
1C Oblivifall - Losing My Religion.esp [Version 1.3]
1D xulTheHeath.esp
1E XulEntiusGorge.esp
1F xulFallenleafEverglade.esp [Version 1.3.1]
20 xulChorrolHinterland.esp [Version 1.2.2]
21 xulCloudtopMountains.esp [Version 1.0.3]
22 KragenirsDeathQuest-CloudtopMountains patch.esp
23 xulBrenaRiverRavine.esp [Version 1.1]
24 xulImperialIsle.esp [Version 1.6.7]
25 xulBlackwoodForest.esp [Version 1.1.0]
26 xulCheydinhalFalls.esp [Version 1.0.1]
27 KvatchRebuilt-CheydinhalFalls patch.esp
28 xulAspenWood.esp [Version 1.0.2]
29 Oblivion Gate Map Marker Remover.esp [Version 1.1.0]
2A KT_KhajEyeToggleNoEff.esp
2B Oblivifall - Ambiant Dungeon SFX.esp [Version 1.2]
2C Oblivifall - New Classes.esp [Version 1.2]
2D Enhanced Grabbing.esp [Version 0.5]
2E Denock Arrows.esp
++ Script effect - Bash icon.esp [Version 1.01]
2F Companion Compatibility.esp
30 Bashed Patch, 0.esp
01 All Natural Base.esm [Version 1.3]
02 Oscuro's_Oblivion_Overhaul.esm [Version 1.34]
03 Kvatch Rebuilt.esm
04 Oblivifall Master File.esm [Version 1.0]
05 Unofficial Oblivion Patch.esp [Version 3.3.5]
06 DLCShiveringIsles.esp
07 Unofficial Shivering Isles Patch.esp [Version 1.4.2]
08 All Natural.esp [Version 1.3]
09 All Natural - SI.esp [Version 1.3]
0A Side's EAX Control.esp [Version 1.0]
0B All Natural - Real Lights.esp [Version 1.3]
0C Dynamic Map.esp [Version 2.0]
++ MaleBodyReplacerV3.esp
0D Oscuro's_Oblivion_Overhaul.esp [Version 1.34]
0E Zombie Diversity.esp
0F Skeleton Diversity.esp
10 Oblivifall - Something's Not Right.esp [Version 1.0]
11 Kragenir's Death Quest.esp
12 KDQ - Rural Line Additions.esp
13 Kvatch Rebuilt.esp
++ Kvatch Rebuilt - OOO Compatibility.esp
14 Kvatch Rebuilt Weather Patch.esp
15 Cyrodiil Travel Services.esp [Version 2.0.7]
16 RTT.esp
17 MannimarcoRevisited.esp
18 MannimarcoRevisitedOOO.esp [Version 0.1]
19 Faregyl.esp [Version 2.0.2]
1A Molapi.esp [Version 1.0.1]
1B PTMudwater.esp
1C Oblivifall - Losing My Religion.esp [Version 1.3]
1D xulTheHeath.esp
1E XulEntiusGorge.esp
1F xulFallenleafEverglade.esp [Version 1.3.1]
20 xulChorrolHinterland.esp [Version 1.2.2]
21 xulCloudtopMountains.esp [Version 1.0.3]
22 KragenirsDeathQuest-CloudtopMountains patch.esp
23 xulBrenaRiverRavine.esp [Version 1.1]
24 xulImperialIsle.esp [Version 1.6.7]
25 xulBlackwoodForest.esp [Version 1.1.0]
26 xulCheydinhalFalls.esp [Version 1.0.1]
27 KvatchRebuilt-CheydinhalFalls patch.esp
28 xulAspenWood.esp [Version 1.0.2]
29 Oblivion Gate Map Marker Remover.esp [Version 1.1.0]
2A KT_KhajEyeToggleNoEff.esp
2B Oblivifall - Ambiant Dungeon SFX.esp [Version 1.2]
2C Oblivifall - New Classes.esp [Version 1.2]
2D Enhanced Grabbing.esp [Version 0.5]
2E Denock Arrows.esp
++ Script effect - Bash icon.esp [Version 1.01]
2F Companion Compatibility.esp
30 Bashed Patch, 0.esp
Any help would be greatly appreciated.