HI
i went on my own on 2002 with them, i was supposed to do 6 weeks but after 3 i came home, 3 weeks of camping with strangers was enough for me! how old is she? i was 30, but the ones under 21 had problems as they couldnt get in the bars as they check your passport.
it was a v good trip that said, from new york to la, ii saw lots of great places, but time was short at some of them, and wanted to spend money and do everything, but everyone was young, studenty and on a budget, so we always ate at the campsite, if shes young and very outgoing and loves the outdoors, then im sure she would love it, i was older, for me it like being in a big brother house but in a very small camper van.
you spend a lot of time on the road too, so tell her to take a book! and a light case, as you have to put it on the roof every night, i'd go in summer when its hot and dont pack too many things as most of the sites have washing facilities.
if you want to know more specifics then just let me know
k