I have towed many 2x4 cars for long distances. If I were you I would put the rear on the dolly, tie the steering wheel off straight, and have at it.
Experience, Honda Accord towed 10k or more front end in dolly, Datsun (Not Nissan) pickup, rear wheels in dolly, steering wheel lashed, 15k miles plus. The pickup acts funky with hard turns, dolly skips, so when I can, I put a load in the bed as far back, up on the dolly as possible.
More projects dragged home on a dolly than I am willing to admit.
Beautiful rig by the way.
Duane
Sent from my SM-G920V using Tapatalk