I would start by looking at several brands of trailers. Get a feel for their layouts. Do you want the garage part of the living room, or separate section with a wall and garage door?
You might not want a garage bulkhead at all.. Your bike does not leak fuel, and your home garage does not reek of fuel leaking, so why worry about it in your RV garage?
Consider models without the bulkhead, and that you will be able to use all that space at once. There are also models with side ramps - both in and out, so you can push in the drivers side and go out the passenger side. This only takes up about the rear 4' of the RV, leaving much more space inside. It would work best with a 4' or shorter bike, but if longer, you can still enter one ramp, just turn to the side as you enter, and will require both ramps open to get out, back up as much as required, then pull out the other ramp.
I would want several "Fantastic" fans in any RV. They can each move out 250 CFM of air, and with 3 of them can remove all the air from the RV every 3 minutes. So if you end up with exhaust smell, it can be gone quickly! I have 3 in my motorhome, and use them to ventilate the RV when it is warm out. By running all 3, and just have the dining room window open, I get a strong breeze past me.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
Kangen.com Alkaline waterEscapees.com