If it's camping then I'd definitely recommend Camping Piantelle which is right on the lake at Moniga Del Garda. We go every year fri a 4 day break.
They have caravans, which are very comfortable, with lots of space.
For Garda I'd really recommend hiring a car as there are lots of little towns to visit, or even drive over from the Uk.
My favourite is Salo, which is about 15 mins in the car from the Camping park.
There's also Sirmione which is very beautiful but busy with tourists.
There's also a large Camping park near Sirmione, sorry I can't remember the name it could be Camping Park Garda?
And Altomincino Family park on the RHS of Sirmione but no lake views or access.
For the kids there is Gardaland to visit, but my DS just enjoys taking the car ferry and boats etc and adventuring around the towns.
Hotels get very expensive at that time of year because you are in competition with German, Dutch, Swiss and Italian holidaymakers who drive to the lakes and it gets super busy.
Another option is Maggiore which is half split between Italy and Switzerland and is less touristy than Garda or Como. You have the town of Varese near by and Lake Lugano is also close for visiting.
One that's probably the least popular with tourists is Lake Iseo which is between Garda and Como. But more natural but doesn't have the lovely towns to explore like Bardolino, Malcesine, Riva Del Garda, Limone etc.