The Minigaig in one day?

Hi. I'm off on a walking/cycling holiday in Aviemore towards the end of
June, and am in the process of looking at full day walks which may be
borderline feasible, and explore areas that are inaccessible without a
lot of effort. A thought flashed through my mind about the Minigaig.
There is an early morning train which goes down to Blair Atholl, from
where it is a leisurely 30 mile or so walk back to Kingussie, straight
north as opposed to the big bend through the Drumochter pass. I
understand the Minigaig could be done in a two day hike with a wild camp
somewhere on the plateau near the highest point. My question is, would
this be feasible in one day if I took a mountain bike and cycled the
sections which were rideable. For example, catch 6:12am train to Blair
Atholl, cycle to Blair Castle then up the track which leads to Glen
Bruar. Cycle to the end of Glen Bruar, then it is likely a case of
walk/carry the bike up over the lumpy bits and the Minigaig summit.
Descend towards Glen Tromie, and start cycling again when a suitable
track is reached, continue on to Kingusssie. Get an evening meal in
Kingussie then catch a train back to Aviemore. Is this feasible or
overambitious?