I was in the process of buying a small toy hauler. After reading the forums I was really worried if my truck could handle it. I have read you cant go over 30 MPH on a small grade pulling less than 5000 pounds. I told the dealer that I was concerned and asked if I could take it for a test "drive". Surisingly he let me!
The toy hauler is a 17 foot, 4070 dry weight. It had 1/2 tank of water in it. I was pulling around 4400 pounds. No weight distribution hitch (in hopes of making it feel heavier since it was unloaded).
I took it out for a 100 mile trip. Started at elevation of 6500 and went up to around 7500 feet. Largest incline was 6-7%. Air temp was about 65 degrees. It was not bad. Truck handled it better then I thought. On the largest hill I was able to go 50 MPH keeping the RPM's around 4000.
I'm going to go ahead and buy it. Once loaded up I'll be closer to 5500 pounds but I'll have the distribution hitch on it. I'll get airbags if needed. I will be going through mountainis terrain but I'm not expecting it to be fast. Just thought id give you guys my experiences.