have just installed the late model already patched/modded & ready for modern Windows machines version hosted at wiwiland.net

have also already modified the z.cfg & DosBox.conf files as per the recommendations of various readily found fan sites

however, before I begin, am wondering about a couple of things...



http://www.uesp.net/dagger/dagfaq12.shtml

Is this still true?

Lastly, as in Morrowind, is it possible when exploring/dungeon crawling to break/ruin various Guild/Faction quests, or even the Main Quest, & if so, does the game provide any warning?

Don't know about the Write Caching thing. Never heard about it either pre or post Morrowind.
IMO corrupted saves are not a problem, but like most games Daggerfall can be buggy.
There is a program called "Fixsave". I've had it help me 1 time. It might or might not be of more use.

Never seen any warnings. And, no, I don't think you can break/ruin any (future) quests just by dungeon crawling. However, I wouldn't dungeon crawl in any of the main quest dungeons (just for the fun of it) until that part of the main quest is finished. (Although I don't think it would hurt anything).
Sometimes it's unavoidable but I also wouldn't make a habit of doing more than 1 quest at a time.

It's not possible to randomly break guild quests or the main quest when dungeon crawling. You can break the main quest by asking certain NPCs for quests then declining or failing them. For this reason it is better to not ask people in Castles Daggerfall, Wayrest and Sentinel for quests until after you know who is who and who offers main quests.