Steve – sorry I’ve done a sh1tload of riding in the ‘Gorms and your post is really misleading.
For sure if you want to pedal around in circles in Abernethy,Rothiemurchus, Feshie/Inshriach and over in Invercauld / Ballochbuie then you will encounter locked gates / no styles etc but the vast majority of these are on unmarked logging tracks. The fact is if you are following the trails marked on the OS map then I really cannot think of anywhere you will encounter a problem.
Last problem I encountered was over in Rannoch about 2 years ago. Bloody great big locked gate, a deer fence style that was all but designed to make it impossible to lift bikes over and a very large ‘no bikes’ sign. This was on a forest road. I reported the landowner to the access officer @ P&KC and got the matter dealt with.
Bottom line the OP is not going to have any problems with gates and fences.