We had a fabulous Easter trip last year at a bargain price. We booked through Red Funnel ferries to the Isle. Of Wight and you get a choice of campsites. we stayed at the Orchard one which had indoor and outdoor pools and other stuff. Charlotte was 11 at the time. Loads to do on the Isle of Wight and camp site was very good. I think it was £130 all in ferry and camp site together for 5 nights.
At Whitsun we did the Jurrassic Coast in Dorset staying in Charmouth. Did a fossil safari (book online) went to Lyme Regis another day. Campsite in charmouth had anf toilets but a fab gym and spa and indoor pool, so we just went to the toilets in there.
We have also done Hillhead in Devon which is a Caravan Club site but loads to do round Torbay.
Enjoy
Zebedee