a campervan would give you a bit more flexibility in terms of the places to stay. however with a caravan you can unhook and then just drive around in your car. whichever you choose you will need to do a lot of planning and forward booking as sites get booked out very quickly during the tourist season. you could also look at perhaps a cottage or bed and breakfast where you travel around bit more expensive but would take into account the odd weather we sometimes get in the uk. also have a look at youth hostels lots have family rooms and it would be a cheap option. how long are you looking at doing this for and which places do you want to visit?