The valley Ailefroide (literally "cold wing") is just within the park boundary to the southeast. It is a wide, triangular, post-glacial valley with a meadowed and forested floor bounded by a couple of streams running through. The road into the valley terminates at a trailhead about 2 km up from the valley, so this is the departure point for accessing the major glaciers of the Ecrins Massif (another entry perhaps).
The valley is walled by the very tall but somewhat discontinuous granite buttresses of the peaks beyond. Thus the climbing is generally multipitch slab/face along with some single pitch on some of the lower tiers. The routes are "equipe". Bolt anchors, bolts at the harder sections of climbing, and established rap lines. The guidebook indicates where this varies.
The open part of the valley is about 1 square km. Most of this area is part of the campground. The valley meadow is vaguely divided into sections but no designated "sites", and there is nice hot water, toilets, dishwasing etc. After camp 4 and even the tuolomne campground (invoked by virtue of their similar setting), this camping is seriously a whole new level of enjoyment. The manager is helpful and you pay when you leave. I think it is maybe between 6-8 euro a night.
The valley is a ski resort in winter. Within walking distance from the camping(maybe a km at the most)there is a tabac/small market for provisions, a restaurant/bar, & gear shop, but they don't open until late junish-mid july. Other than these places there is really no other indoor refuge and weather here hits hard, sometimes for days on end, though apparently it's supposed to be a fair weather spot in the southern alps (??) Also apparently it gets very crowded; in the early season there were not many people at all, and nearly all were English (or at least English speakers).
The best source of detailed climbing info would be local sources- guidebooks (you can get it in the area or in Chamonix or other sporty areas). Some local people have taken the effort to put great info online (in English!) as well. There is nice bouldering here too. Arguably this spot is total world-class beauty.
Getting There
Without a rental car this was not super easy... The nearest town that can connect to the national rail system is L'Argentiere La Besse, and there is a bus between here and Vallouise, which is the closest "real town". Vallouise is maybe 8km down the valley from Ailefroide village. In the towns, it is not Chamonix, expect to speak French!