Was having a look on TrailScotland and came across this
http://www.maryqueenofscotsway.com/
Stages 7,8,9, and 10 from Glendevon via Glenfarg, Falkland, Ceres to St. Andrews, mostly through Fife, might make a good weekend ride in the summer. Although some of it is tarmac on quiet roads most of it seems to be offroad, like the part that goes up to John Knox's Pulpit then down Maspie Den to Falkland.
I've ridden up to John Knox's Pulpit several times so if I can do it and the rest of the route is no more difficult it should be very enjoyable.
Having said that, we walked up to JK's Pulpit on Christmas Day and parts of track had been damaged by all the rain. Rutted badly in a few places, will only get worse with the continued pish weather too.
Oh, and the sandstone crag at JK's Pulpit has some large blocks of stone teetering on the top ready to join their pals that have already fallen off.