Blimey, you are indeed in luck, as wiltshire I believe has the most amount of BOAT's out of all the counties.
Tip of the days, buy an O/S map 1:50000 scale, and look for the
+-+-+-+-+-+ they are Byways Open to All Traffic (BOAT). If you go out to Sailsbury Plain's check with the military first about live firing..... I kid you not
Oh and don't ride alone!!
Above all Enjoy
Edit: If you register on
http://www.trailbikemag.com forum there is a chap called "38thfoot" who goes out a lot on the plains, I a sure with the encouragement of a Bacon S/w & a mug of tea who would show you the ropes!!