Don't mean to be personal, but how bad is your disability? Have you considered a coaching holiday.

I used to be a tour guide for a coach holiday company.  We had lots of partially disabled, and elderly people who couldn't walk far.  Loads of singles too.

They were away for a week, with 3 trips out included in the price, and two more optional ones. Some of them included some walking - or being in a city for a few hours, but many trips were to a particular attraction, or a river boat trip etc.   Do a bit of research before you book to see what trips they do and if you think you could do it.

Often, clients would opt out of trips and sit on the beach or do their own thing at their own pace.

Try to choose somewhere flat and easy to get round - not Torquay or St Ives - too hilly