Oh how I wish that these priority modes adjusted ISO and exposure, too.
Because I am really, really bad at realizing that I need to adjust them before I get back inside to a whole CF card full of dark pictures. The good news though is that I think all of it finally clicked tonight as I went back through the pictures and could see where some things were too high and others were too low and I *think* I now know how to fix it...
Certainly the indoor pictures I took came out better than they had previously.
There's still not quite enough light, but at least I am figuring out where/when to adjust things to the right levels to make IMHO dramatic improvements.