Is there much of a learning curve on the driving of the 40foot tag of over the 39 foot single ax.?
I think the big thing you'll find in driving differences is that your wheel base if probably much further apart with the bus, than with the motorhome. RV's tend to have rear wheels forward quite a bit, with a large overswing in the rear.

Buses have the wheels well towards the rear, so there is less overswing to worry about, however you have to swing wide to not clip your sides. Drive using the mirrors, and try to watch that your rear wheels are close to clearing the curb before making a right-hand turn, and you'll be ok. Generally stay on the high side of a turn.

Otherwise, you'll find that there is no comparison in the ride between your bus, and an RV. It will be a VERY pleasant change.

Ray