I don't do motorway driving, so go to places I know that I can get to on decent roads, or take the train. It is just a matter of looking at what is in the area that you go to and if there is enough there to do. Often when I go away, we never go out in the car anyway.
We go to Weston-S-M, and they have the beach, the pier, a kids play/water park, a swimming beach, a climbing park, a big wheel, a massive funfair all summer (used to be an aquarium but it sadly closed down). There is so much to do that we don't need to go anywhere else. We stay in the PI on the sea front which is a short walk from the train station.
I don't know where you live, but if you could find something similar that you can get to easily, you could have a great holiday.
In the past we have been to Dawlish and Paignton, both accessible by train, and used the local buses to get to the Zoo or other towns nearby, Dawlish Warren, Torquay, Babbacombe model village etc.
We went to Bath by train, stayed in a fairly central PI, went to the Abbey, the Roman Baths, did the 2 open top bus tours and went to a massive park, and also had a wander round the shops.
There is so much out there, you just need to look at the stations, accommodation and what is nearby/bus routes etc.