Annie, usually I hold the book and sit upright. The Law text book is pretty heavy so it's kind of an upper body workout too.I did find that my yoga mat laid across the handlebar is a great bookstand, too.
As for the weight lifting questions, I'm certainly not trained in weight lifting, or anything, really, but I've tried lots of things over the years, so I'll still comment.
The general rule of thumb that I've learned is that light weight with lots of reps works on endurance and lean muscle, that medium weight and medium reps works on strength, and very high weights and very few reps works on power. I've done workouts that are pyramids - one set of each with each exercise, workouts that combine weights and cardio - ride the bike between exercises, etc, workouts with lots of reps and lowish weights. The most interesting thing from all of those different things is that I think my muscles learned from each experience and, even without continuing the same routine, my muscles seem to remember. The power workout was most interesting - I did it for only a few months in an effort to increase my explosive power on the bike. It did not lean me out at all but did improve my mtb climbing tremendously. When I switched out my routine to less weights, and sometimes no weights (I go through lazy and busy phases like everyone else), that power for climbing is still there, and the bulk I seemed had gained at the time did go away with other routines.
For best calorie burn, I've read that working out the biggest muscles groups - your legs and butt - is the trick. Lunges, walking lunges, all the different squats, one legged squats, sissy squats, etc. I always prefer upper body workout because I see the results so quickly, but I remind myself of the whole butt and hips thing and try to include it....
Anyway, hangirl is trained in this stuff, so I think she can probably tell you way more.
Hugs and butterflies,
~T~