Hi oakvalley,
Congratulations on your new rig and welcome to the Heartland Owners Forum.
There are a lot of Prowler models and even the smallest ones currently shown on the Heartland website have a Gross Vehicle Weight Rating (GVWR) of 6,900. If you look at the label on your trailer, usually at the front, it'll show the GVWR. That's the number you want to be able to tow.
Also, the towing capacity of your truck will vary depending on model year and other factors.
You might want to visit
FifthWheelst.com to consult tow ratings and worksheets to figure out what's safe.