An ex-Mendips local here.
There’s some cracking riding to be had, just make sure the weather is good. As above, the area can really suffer in the winter months. We used to regularly meet at the Crown at Churchill and ride a loop around the Rowberrow / Black Down / Burrington area.
Google will give you a few ride ideas (here, for example) but I think you’d be better off with some local knowledge to fill a weekends’ riding.