There are a couple of nice campsite down by Dornoch or Embo beaches, both are very nice beaches, and dornoch is a very nice small town, only about a 10min drive up to the trails, there are also a couple of hotels in golspie itself, the Ben Bhraggie hotle and the golspie inn, but i am not sure what these are like or what sort of prices they are.
While you are up there I would recommend also taking a trip to Balblair, it is up just beyond Bonar Bridge, and is a very nice quiet trail which isn’t used all that often. It is more geared towards xc with some quite technical sections.