Solo vacation ideas within driving distance for a few days?

I have a few weeks before I start a new job so I thought I might get out of town for a few days or so and have some fun. I'm new-ish to the area so I don't really know what places there are, but I should be able to find something within a few hours drive, right? (I'm currently in South Bay BTW.) I'm open to ideas -- day hiking, music festivals, new town to explore, maybe? Just no camping since I don't have gear. Planning to AirBNB wherever I go. Just looking for fun solo things to do.