Chartreuse is a mountain range located in the French Alps
Flora and fauna
Mainly forest and alpages
Mild summer, snow from december to march
Due to the topography, only a few roads lead to the area.
Transisere runs a few bus per day [] Hitching to and around Chartreuse is pretty common and there are chances you eaven have to wait to get your turn!
Fees and permits
As all Regional Nature Park (PNR) in France, there is no entrance fees to enter the area
See "Get In"
With altitudes up to 2082m (Chamechaude), Chartreuse offers a wide range a hikes and walks.
For information, head to one of the tourist office (Saint Pierre de Chartreuse, Le Sappey...)
La Maison de la Montagne (3, rue Raoul Blanchard, Grenoble) is really helpful with a nice selection of books and maps of the area (free consultation)
There are several nice climbing crags in the area.
Poeple looking for sport climbs should consider buying the guidebook "ze topo" 
For really hard stuff, head to "l'Abatoire", with routes ranging up to 8c.
Multipitch and trad
Trad routes and multipitch are all around, info available on Camptocamp  (available in english)
Due to its karstic topography, Chartreuse is not the best place to go for a swim.
However, to escape the summer heats, you still have some options :
Lodging & Camping
Check on http://chartreuse-tourisme.com/ for accomodation.
Tolerated pretty much everywhere, around villages try to ask land owners if its OK to camp.
Many huts are free to access. Check on http://www.refuges.info/nav/2/massif/Chartreuse/ for a full list