Frilf
Explorer
I'd say as a general rule to NEVER, ever, ever, ever, let the DM or another player run someone else's PC (unless your group are incredibly understanding or else you'd like a particular someone to leave). Whatever else you do outside of this one cardinal sin of RPGing is up to you. We generally use the "portable hole" method when in the middle of a dungeon crawl (no good "stopping point") or have that PC off running menial errands (when there is a good "stopping point"). Dungeon fever sounds intriguing to me, though. Our group might try that sometime 
Cheers!

Cheers!