We usually stay at BC/YC, and can tell you that we are relatively spry (for our mid 30s) and at a good clip, it's probably a 20 min walk from BC to the monorail...then you have to wait for it. Then you have to change monorails and transfer to the MK monorail from the TTC. It's a lot of work.
BC buses can get crowded at open and close, but if your husband wants a seat, make the much shorter walk over to the YC, and grab the bus there. That resort gets picked up before BC, and at the end of the day/evening, get off at YC and walk back. YC gets dropped off first.
We've never waited for a bus longer than about 15 minutes at BC.