Phil
Try 'La Quercia' in Lazise. It is a large site with allthe amenities should you want them, but enough quiet areas if, like my wife and I, that's what you prefer. Lazise is a beautiful town with a ferry stop which allows you to explore the lake. The town is also excellent for access to verona and Venice being at the south end of the lake. We were in the site in the middle of May last year and I can assure you that it wasn't busy. They also allowed be to book for 4 days although, in the end, we stayed for 8.
Lawrence