Epic day's riding. The full day (Inners - Selkirk - Inners) is definitely too much for the national (35 miles and 4900 ft climbing, although we may have taken a wrong turn or two), but we all agreed it was still a superb day out. Once we got out onto the hills, the mix of natural riding reminded me of one of our highland jaunts, so getting that down in the borders is really a bonus.
I think we have a route that fits the bill for the national - 20-25 miles (still need to do the GPS sums) where we get most of the good riding, superb views for the lunch break stop, and ending with the full Minch Moor Inners Red descent.