HK, yeah, 11 hrs. is a long drive. On the other hand, you'll probably arrive after 5 pm, meaning that you can skip the bus and drive right to Maroon Lake. Crater Lake is only 1.8 miles from the trailhead, and the locals told me that the 11 designated sites are rarely all filled on weekdays. Anyway, it beats paying $$$ for a hotel room. As far as the loop itself, I didn't train at all, and did it in three days. But I live in mile high Denver. You certainly won't be bored if you take four. I didn't see any UL hikers out there, but there's
no reason you can't do it that way. My base weight was around 11# but I added three pounds of camera gear to that.