I used to tow a decent size travel trailer with my 2003 5.3 Silverado with 4.10 gears. Did just fine in the hills of western MD.
Now I just two my fairly light tin rig.
Does the trailer have brakes? You will definitely feel it when it comes time to stop. Also check the condition of those brake lines.
You never know when a small dog will run out in the road causing you to slam on your brakes blowing a hole through the corroded brake line and having brake fluid leak out making your brakes not work. The you will have to nurse it to a parking lot and sit there until your wife comes to get you so you can grab the RV and tow the boat back to the house.
Ask me how I know.