...and ended up right back to the same mod list and load order with the crash gone? For me it was right outside Desolate Mine. Sometimes it would crash while fighting the goblins outside, but if not then it would always crash exactly at "I have found Desolate Mine." I mean, the crash was repeatable always at that instant. So I disabled my load order of everything but FCOM, Xenius Races for my character, and the Unofficial Patches and Unofficial DLC patches. From there enabling mods one by one, sometimes two at a time, restarting Oblivion again and again. THREE HOURS chasing a mod crash culprit that vanished like a fart in the wind simply just because. When the exact same load order and mod list before was a repeatable crash. Why?!

Could have just been a bad spawn. Did you try just going to an interior cell and waiting until your respawn interval had passed?

Sometimes crashes are caused by random things like an NPC's AI package or a different critter spawning at a nearby location. If they move or spawn differently, the crash condition changes and you're left scratching your head.

EDIT Stromgarde beat me to it...