My first husband and I had a 1984 Catalina 27 that we towed with a 1/2 ton Chevy truck with 454 engine at the time. We towed it from Fresno,CA to Ventura,CA over "the grapevine" a few times. In fact we picked up the boat when it was new from the Woodland Hills factory and towed it home. It looks funny cuz the boat sat so much higher than the truck. When looking out the rear view mirror you had great visability cuz you were looking under the boat at the traffic behind you.
I recall that the truck handled it fine, although at 84K miles we did have to replace the transmission. Anyway we just stayed in the right hand (slow) lanes. We always went down hill in a gear lower than we used going uphill. I believe that was to protect the brakes on the truck and trailer.
Hope that info helps.