The easy route from Prestwick (Graceland) to Dumfries is to take the train north to Kilmarnock and change there to go south do Dumfries. Total 1 hour 45 minutes and should cost less than 15 pounds. Notice that if you're flying back to Torp and staying the night before in Dumfries, the only possible day is Sunday. There is no train early enough for the other days. Only option is to stay that night in Glasgow.
Personally I'd not plan on Dumfries plus other towns in one weekend, but there are pubs and castles in that area and probably destilleries too. IMHO one destillery is enough, they're basically all alike.
Pm me if you want to chat about Scotland in norwegian.
Vin gardu pro la sciuroj!
Bookmarks