Welcome Drag! Former bike drag racer here. Also using my shortie as a tow vehicle.
First piece of advice before towing-GET AN EGT GAUGE! These things WILL tow ok-but the vans have no intercooler like the trucks-you gotta watch it on the hills. (says the guy who cracked a piston being stupid up a big hill
I have a propane heater out of a discarded pop up. Our last race of the year is in Northern Vt--in mid Oct. So 20's at nite-40's during the day. I have no added isulation. Its just enough for that. Anything warmer than that its great.