Two weeks in France, tips?

Hello

My girlfriend, myself and our boy and girl, who at that time will be 7 years and 9 months respectively, will be driving by car from Belgium to the middle/south of France on holiday in July. We plan on staying for two weeks. We'd like to have some comfort for the baby and a pool/entertainment for our son, but we've got a limited budget. Do you think it's best to find a vacation house for rent, or are we better of renting a chalet on a camping site? Any other tips? Thanks in advance!