We quite often pull our boat behind the TT so bikes at the back ...no
On the front of the TT also a no, we feel the back up camera on the Avalanche would be blocked.
Nothing is in the bed of the Avalanche or stored in the boat.
Our spot for bikes...Even with the long slide in on our 27' TT there is lots of room to walk around and use anything. We put my bike, with a quilt around it standing beside the bed, fits perfectly. Hubby's bike, with a quilt lays on the floor in front of the bed. We can still get in the TT if necessary and nothing has been damaged carrying them this way.