Tough Pulling... Truck not strong enough???

Hello All! I just got my first Airstream and love it! I had to tow it 300 miles to get it home and found it tough making it up the hills. I have seen pictures of people pulling Airstreams with SUV's, but after towing with my truck I am wondering how they do it (or their trailers must be much lighter and smaller than mine). My truck is rated to pull the trailer okay so I thought I would have less issues. I my truck is stock and I haven't modified it, so not sure if there is anything I can do there. I was towing with both the truck and trailer dry, so at the minimums it should have been okay. It was okay in town, but once I got on the highway was where I saw performance issues. I normally run around 1800 - 2000 rpm at highway speeds, but with the trailer I was at 4000 rpm on the flat and then up to 5000 on hills with the engine floored to maintain speed. I would have to slow right down on hills to not top out the engine and would be a bit of a risk on the road with traffic flying by at twice the speed. Any thoughts would be great!



Truck: 2007 Toyota Tundra TRD 4.7L (smaller V8 for the 2007 model)

Max Towing Capacity: 7800 Lbs

Payload: 1400 Lbs



Airstream: 2010 International Sterling 27FB

Hitch Weight: 770 Lbs

Base Weight: 5,824 Lbs

GVWR: 7,600 Lbs



Any advice appreciated :)