We do seem to have side-tracked to the issue of immigration and not the problems of visiting as the post was intended.
I did take Toms advice and looked at the requirements to enter the UK;
US citizens do not require any type of Visa to visit the UK for short periods (nor do we to visit the US for upto 3 months).
Unlike the US policy of frowning on return and regular visits, the UK states "The Entry Clearance Officer may decide to make your visa valid for a shorter time than you have asked for, for example if you are not a regular traveller or have never visited the UK before." which suggests that you would be more welcome to make regular returns (ie an RVer coming every 6 months to tour).
The UK offer a Long Term Premium Visa which "identifies the holder as a person
known and trusted by the UK government".
I guess the only way we get one back at you guys is by charging you $430 for a Long Term Visa.

Paul