Hi again Seth...
Just got around to trying your method, works like a charm.
I should have thought to use normal markers for this, but the "From=Now, Thru=Now" markers seemed intended for things like marking song in/out times. I think it was just the name of those markers that threw me off. I can't see myself ever using them again for anything, as markers that don't get saved along with the rest of a project seem pretty useless to me. Maybe there's a good use for them, but right now I can't think of one, and I don't really care. ;^)
Enabling "Stop at Project End" seems to have some sort of intermittent bug regarding end times during playback in the DAW versus end times in exported audio files being different. Repeating myself again I know, but I can only come to the conclusion that has to be a bug.
At any rate, this is most definitely closest to what I was after in the first place, and very easy to do.
Thanks a bunch man, I really appreciate it!