It would take months to do a full tour, there's so much to see and do.
I'd also love to see the Scillies and the Hebrides/Western Isles - I have a bit of a small island fascination. I've been to Orkney, but was scuba diving so only had a one day tour of the main sites, so even though it appears to be a few bleak and empty islands, I'd probably go back, Maybe spend more time looking at northern Scotland on the way up, rather than just going straight to Orkney.
You could spend a good couple of weeks seeing the sites of Yorkshire. Lovely coast, hills, museums, historical sites, city parks, great food, waterpark, moors, Yorkshire Sculpture Park, which is probably the first thing I'm going to do when it opens as I live fairly nearby and go quite a lot, but it's closed, so can't, even though would fit within the 'short drive for exercise' criteria and I know where to park on the edge to walk in, I'm worried that I'd be turned away by security or given a talking to by the police.
Right now I'd be happy to drive to one of my favourite walks in the north York moors, Peak District or Yorkshire Dales and be able to go for a walk followed by a pub lunch.