My wife suggested instead of renting a car and a cottage we kill two birds with the one stone and hire a campervan/motorhome instead for our next visit to the UK.

I like the idea but do have some concerns. The main one being the wife’s ability in negotiating narrow roads. It would seem only the larger vans have toilet facilities on board which I imagine can only make driving more difficult.
Considering hiring one doesn't exactly come cheap - we could have two weeks car hire plus self catering accommodation for not much more than one weeks van hire - I'm beginning to doubt touring by campervan will be any more enjoyable.
Anyone have any experience of this sort of holiday? Positives versus the negatives?