If you encounter a dealer who will not let you thoroughly test drive the motorhome... {and this is the first time I ever heard of such a policy. :h}
"Run Forrest Run!"
I can see them objecting to hooking up a Toad, lots of gear that needs to be in place. If the test drive {that did not happen}, had gone fine you would have no problems towing your Jeep. Perhaps a little tweaking to get your TOAD set up dialed in but everyone goes through that.
Not surprised the dealer is "willing" to talk about trading up. :S