Where to put the stinkin bikes

"5. Inside the unit? Good maybe for one unit which we have done also, but with the two opposing slides in the main area it's also not convenient."

As a dedicated cyclist I draw the line at inside the TT...no! I rack the bikes, one or two, either on the roof rack of the Tahoe or on a hitch mount I bought from e-trailer.

Have you ever looked where the bugs hit the front of your 5er? Most likely mostly above the height of the bikes. Mounted on the front of the TV more bugs, blocks lights and air flow to the engine. Ever think of a cover for the bikes on the front of the 5er?

Have 4 place bike rack mounted to rear bumper of coach since new. Still solid as a rock and no reinforcement of bumper. Had 4 bikes on there at a time. strapped down w 3-4 straps, never moved. You could buy our coach and bike rack goes w/ it.

I built a pin box rack that uses nitrogen struts to raise and lower weightlessly the 2 bikes from on high to shoulder level on the ground. Bikes hang by the wheels, not frames. It uses 4 1" square tubes from the mount up to the rack so that the rack remains level while lowering or raising it.
The rack bolts to the sides of standard 12" pinbox, extends forward and up to the same height as the 5er overhead, to a 2" tube 42" long with plates on each end with 2- 3/8 bolt holes 2" apart vertically, 2-1/2 apart horizontally, to which the 4 vertical 1" x 40" tubes bolt. At the top of these tubes, the rear of which has a x member, a 1/4x 4" x 14" plate with the same bolt pattern, cut slim, tapered from front to rear with ' u' shaped offset height channels to hang the wheels in, padded with slit and glued 3/8 id rubber hose. No clamps, not even a bungy cord to keep them in place.
200# by 8" stroke nitrogen struts with the base inside centered on the front vert. arms and the top on the rear arms is right for our Schwinn Mt. bikes. . A travel stop and auto spring lock pin at each elevation.
Bikes ride so high so that even a short bed truck can turn when loaded, when pulled
down to un-or load its at ground level.
The only issue is in raising or lowering the empty rack. Without the weight of bikes, it takes a handle or rope to pull it down.
Bugs on the bikes are a lot less trouble than road dirt and rear bumper bounce. And we can still pull our boat or M/C trailer.

Buy some beater bikes that you don't care if they get hit by rain/bugs/slop and put a mount on the front of the truck.

We use a Curt Front Mount hitch on the truck with a Swagman XC2 bike rack. Very solid and I like having my eye on the bikes.

You could check out a Thule rack that mounts on the roof of the truck. You could use Geeza bike covers if you wanted to keep them clean. If I wanted to haul a couple bikes that is what I would use.

I bought a Curt 2" hitch receptacle and bolted it to the frame, then installed a 5-bike hitch mounted bike rack. I do have to hang the bikes vertically so they don't stick out but it works pretty well, and I bungee everything together so it doesn't move around as much. In hindsight I probably should have just installed a regular hitch at the back of the trailer so I could mount them horizontally but this works pretty well. I think either is better than trying to utilize the bumper, reinforced or not.