Thanks Maya and Soup for your input. We registered D today for the Independent study program. I think she's going to really like it, actually. Her advisor is a really nice guy.
D will go for four classes a week - (each class once a week, 1 1/2 to 2 hours long). So she'll go for about 4 hours on Tuesday and 4 on Thursday. Assignments are given for a month at a time, and handed in at the end of the month - at which time they also take an exam. She'll be responsible for pacing the work, reading and learning at home, but obviously will also still have a fair amount of class contact (actually, I suspect one two-hour class might contain as much real teaching as three or four 50 minute classes at her present school). Also class size will be smaller, since there are only 20 freshmen in the whole school.
I've questioned D repeatedly about whether this is really what she wants - something she said today to the advisor really struck home - she wants to "separate her academic life from her social life". Bingo!!! This is a girl who really does want to do well, but found the social distractions and impetus to "dumb down" too much to handle.
We'll see how it works, no guarantees of course, but I am hopeful.