I've driven in a van from Loch Laggan to Corrour Lodge. From memory it was slow going, about an hour to do 15 miles. Not a particularly pleasant route, to drive anyway but sure it would be OK if not a bit monotonous on the bike.
This was about 15 years ago I reckon, when they were getting the new lodge ready to open.
It is / was a spectacular place, modern building with games room. They were building a big artwork mountain made of loads of sheet metal when we were there. We got a bit of a tour of the lodge - very impressive.
If I was doing some of these munros again I quite fancy walking in from Corrour Station past Loch Ossian.
All the best