Park both units nose to butt and make a measurement. Allow about 3 feet between the 2 units for moving around in between them in the trailer.
This is the minumum length you need.
Add about 4 or 5 ' and that will be the length of a trailer needed. If you plan on hauling your luggage and etc in there also, add another 2 or 3 feet. Now find a nice big 3/4 ton pickup to pull this setup. Might want to consider a Diesel 4 speed unless ya splurg for an Allison automatic transmission.
Once you have bought the trailer, then it is laying out the place to add chocks for securing the units to the floor.
The back unit needs to have a removable chock so as to be able to get the front unit in and out.
What he said AND I've noticed some larger dealers have trailers there with the MCs. Or just go to a trailer dealer and look at flea bay but R J nailed it. And you WILL want some tie down pad eyes in the floor. And DO NOT skimp on tie down straps. In a hard stop they only have to fail once. Conversely good straps will cause you no worry in a panic stop. Also you can have too many tie downs on as often as you want if thy are attached correctly-you can have too few on once! I used to pull flatbed all over this country. NEVER once dumped a load. RIDE SAFE.