I used to tow a 4,000 pound Cherokee behind my motor home but now I'm towing a 5,000 4Runner; however, my '03 E-450 motor home at 11,500 pounds is 3,000 pounds lighter than yours. These are actual scale weights. I have found a few grades in Colorado that are steep enough and high enough that we unhook the toad and drive both vehicles for a bit. You have a lower first gear than I do so you might not have this problem plus the mountain passes in Oregon aren't very really very high. I've never had to go below second gear for Washington and Oregon mountain highways. After driving several days with the toad in tow, I unhook it and my motor home almost seems sporty. Anyone who says you won't even notice the toad back there doesn't drive in mountains.
