I had a 20ft Searay which we trailed to Lake Annecy in the french Alps. Stopped in lakeside hotel with own mooring. Fresh water 20 deg C and more. Highly recommended. Also did same to Lake Como in Italy, same sort of thing but camped on the lakeside instead of Hotel, also cheaper. Also took sports cruiser to South of France two years ago,BRILLIANT, stayed on board at various marinas but would suggest Port Grimaud as it is particularly pleasant and has plenty of waterside accomodation for rent, many with mooring. Plus launching facilities etc. However there are plenty of other options. Timing is important. 1st two weeks in August for guarenteed weather in Mountain lakes. On South of France the same two weeks are very busy so book ahead. We are going S of F this year last two weeks August. Weather still good and less of a scrap for moorings ( the smaller the boat the easier it is). As for the best, they are just completely different.