The pub in Ampthill is the Old Sun, they have a road section which go out on a Thursday night also.
From Ampthill you will also find the riding at Chicksands can be OK especially in the winter as it drains pretty well.
Then you have the trails around Millbrook woods and also the new bits around the centre parcs site on the edge of Flitwick.
Basically there is plenty of riding, what do you ride as I am local and will say hello if I see you around. I ride a genesis altitude mostly for the local stuff.