I have just got back from Bleau and it delivered once again! Quality conditions and not too busy, which might be a result of Brexit uncertainty.
When camping we have tended to avoid La Musardiere as when I last stayed there it was too busy and noisy in the evenings.
A great alternative is Ile de Boulancourt (translated - Island of Boulancourt) which is a beautiful spot with great facilities. €7.50 a night and decent price on quality pad hire.
I would recommend it as a great spot for families and those who want to avoid the crowds! Last week we basically had the place to ourselves (15 of us there on a school trip).
It is a bit further from main bouldering areas than La Musardiere, but that is a price worth paying for peace (and security of property).
The nearest large bouldering area is Buthier within 5 mins drive.