Campsite in Angers (Lac du Maine) recently changed ownership and I've not stayed under new ownership but was warned off by others - expensive, not very good and only useful if you are doing something on the lake. I stayed a short distance to the north in Avrillé (not much in the town except shops/restaurants but nice campsite, good for cyclists).
Campsite at Amboise is massive and it's a touristy town. Campsite can get busy but they have a separate no vehicle area for tents. The town is nice to wander around and not horrendously crowded when I've stayed there. Book ahead online.
A lot of French campsites are now using the online booking services which charge a booking fee and some (eg Amboise) wont even accept telephone reservations but say to go online). For 5 maybe less of an issue but as one person the booking fee can be a significant amount on top of the overnight fee. also, when booking day before the online booking systems are a nightmare as you book in the evening and get "We're checking your reservation and will let you know when it's conformed as available" ... then next day arrive, check-in, get setup, make coffee, etc. then get the e-mail from the booking service "Your reservation is available and confirmed". I try to phone ahead.
But on a shorter trip I'd expect your camp sites to be determined by daily distance rather than the site itself ie start end end points defines, given number of days so you'll want sensible distances between overnights not a fee 10 mile days and then a massively long day.
Ian