Hi,
We stayed several times at the Chateau de Chanteloup, only for a few days usually on the way to somewhere else. But it's a good site - very friendly owners, good swimming pool, no static caravans or tents, purely a touring site - with the caravans arranged around the edge of big circular fields
High lights - possibly the best artisan baker in the Sarthe delivers (or did) bread, croissant and pain au chocolat each morning - seriously these are very, very good
Le Mans itself has an interesting cathedral, market square, old town and weekly market and the surrounding area is good to explore. I particularly liked the shop that specialised in all things relating to Herge's TinTin
Le chateau de Chanteloup also hosts several of the independent race teams for the 24 hour race - as a base station away from the race track - unbelievably busy for that weekend.
Robert