Early in my working life I was a trucker. I had the dubious pleasure of driving a IH tractor pulling a dump trailer usually loaded to about 75,000# gross wt.
That little tractor had a six cylinder gas engine of 450 C.I. and about 175 hp. No engine brake, no exhaust brake and drum brakes very similar to those on many motorhomes today.
I hauled over the hills (small mountains) of western PA and WVA for over two years in that little rig without any undue stress on me or it and finally got promoted to a big rig with a diesel and another trailer axle. Life was good.
Bottom line, use what you have effectively, don't get in a hurry and stay within your comfort zone. Don't let the car drivers around you push you beyond the point where you are comfortable. You'll do just fine if you are like the turtle, take your time and relax.