Trip Paris - Le Mans

Hello, I apologise if this is not the correct section to post this question in.
I am planning a trip for a huge group from Paris to Le Mans. Ideally, not the direct route but with some nice (scenic) roads. Already working on this. What I would need your help with is this. I need to find a place approx. half way through where we can have a rest break. Ideally a nice hotel with ample parking (for about 60 cars) that can offer a coffee and bathroom break. Or a nice country house with big premises may also be an idea.
I am thinking of driving north of the A11, through the Parc naturel régional du Perche. Time-wise, North of Chartres may be a good place to stop.
I would appreciate any ideas for an ideal place to stop by you. Thank you very much in advance!