Rosa- there is a book about Whitney that has some info on the HST. I don't remember the exact name of the book and could not find it on Amazon, but I did see it at REI. Its title is something about "Whitney from all directions", or "50 ways to Whitney", or something like that. Each route is numbered and there is a brief written description. The HST section is only 4-5 small pages, but it does have elevation profiles and some other good info. Nice to have, but not critical.
The trail starts about 7000' elev. and stays pretty much at that elevation except for a couple of passes. Kaweah Gap and one or two others. Of course, there's a lot of ups and downs in between, but nothing too strenuous.
It is a great trail and can easily be done in 8 days, although 10 would be nicer. There are a couple of places that would be nice to layover. Kern Hot Springs comes to mind as well as some spots on the Chagoopa Plateau and Big Arroyo. You'll like it.