Gentlemen, we have 2 different arguements going on here.
trailer vs. flat tow
tie off towed M35 steering wheel vs. not tied off
At least 5 people on here have done each and think it is the best way. Since it worked for them, you can't fault their reason for arguing for that option. The original post however ask what should he do? It is kind of like a word question from high school that you know has a trick answer, but can't tell what it is. You can't answer it because we don't have enough information:
How much does he want to spend or not spend?
Does he own a 3/4 ton or 1 ton truck with a gooseneck trailer big enough?
Has he ever driven a M35 before?
Does he own a tow bar?
Does he have a set of lights and a cable to hook the lights up 35 feet away?
How much time can he spend on the recovery?
Does he have somebody who knows what they are doing coming along to help?
Does he know what he is doing?
Anyway, back to the arguements.
I think flat towing M35 to M35 with the towed front tires at at least 60 psi, the tow bar all the way out to the 7th hole, an air hose run to the towed air pack from the towing truck and the cable for the lights run down the passenger side of the towed truck (So if the tires do turn and stay pulling into a tight fuel station or something, it will be easy to open the drivers door, turn them straight and move on down the road.)
I have this opinion because I have about 700 miles flat towing 3 different M35's with 3 other M35s and a M715. I learned to put the front tires up high or they will turn against you. Same with the tow bar length. Make it short and the tires turn. Make it long and they are happy 99% of the time.
Yes, paying somebody else to do all the work is the easiest option, followed by a trailer and then the flat tow as far as the easy scale goes. However, the investment scale is pretty much inverse to that and what a good number of us use to figure out how we are going to do something.