We have a 21' Amerilite. I tow with either a 2010 F 150 w/4.6 v8 or a 2013 ecoboost.
I used to pull it with a 2006 F150 w/4.3 V6 with no problems. I added a tow package to the V6. I don't think It wasn't even offered with one.
The trailer weighs about 4500 loaded for camping (per scales).
The previous owner of the trailer, towed it to Florida from Oregon without hooking up brakes. His expedition only had a 4 pin flat plug, so probably no tow package. He said he had no problems.
I wouldn't want to tow it without brakes.
Just saying you might not have to look that small to stay under 5000lbs.