I've flown to Ronaldsway and driven to Andreas.
The 1st is fine, of course. Watch out for the sudden fog etc.
The surface at Andreas is dreadful (crumbling tarmac, with huge chunks loose) and I would not want to fly there unless I was going to have a prop overhaul afterwards anyway.
There is a 3rd (big) runway there somewhere but is not allowed to be used. They IIRC used to have annual events there. Such a waste...
The water crossing is a non-issue. From say 6000ft you can almost see the IOM, on a good day.