If you want a genuine adventure the Cairngorms are the place to have it.
You can park up at the Linn of Dee-
And from there you won’t see another person or tarmac for around 35 miles by riding up through Glen Feshie-
Which then descends on some lovely singletrack to the other side of the Cairngorms-
From where you can go up, and then down, Carn Ban Mhor, which is a lovely mountain with stunning views-
Before you arrive in Aviemore-
And go to the pub for the night-
The next morning you can then use your sore legs to climb Cairngorm-
Then descend Cairngorm toward Ben Macdui-
Then descend Ben Macdui to Glen Derry-
Then go home. Two days, around 80-90 miles, around 75% off road and two of the best descents of your life, as well as staggering views.