Starting at Abington, up the road to Wanlockhead and down the Mennock Pass to Sanquhar, then back via Crawfordjohn to Abington.
There is a couple of shops and a cafe in Sanquhar, but I'd bring a packed lunch.
The Lowther Hill climb to the "Golf Ball" is optional and very weather dependant. Might be too low clouds, given that this is the highest riding route in the UK.
Pack a rain coat just in case!