To paraphrase Franklin D. Roosevelt, You have nothing to Fear, but Fear Itself.
With your rig, shouldn't even know it is behind you.
If it seems to start getting too fast going down hill, slip it into a lower gear.
If it seems to be bogging down going up a hill, slip it into a lower gear.
Using lower gears can save your breaks as well as keep the motor working better.
We have made it up some good grades out here in the west when towing out 16'
Scamp with a Ford Ranger V-6.
Best of Luck!
PS:
Only been in the Duluth area once (2001), came up from Twin Cities, crossed over into Wisconsin as we got near Duluth (Just to say, we'd been there), then looped into Duluth.....may have gone over a tall bridge....seems like we did. We were in a C-Class MH at the time. No problem in doing the loop.
Then drove over a smallish lift bridge (Duluth Harbor Area) onto a long split-like peninsula or island, just to see the place. Then we drove up the road to Canada. Worse road we've been on for being rough. Had to get the drain plumbing fixed after we got home after the drive. Leaking when showering.
On the way back to Twin Cities, we spent a day by the Harbor, then overnighted at the Wal-Mart. I remember it being very hilly getting up from the Harbor Area.