2018 F150 For 1989 Jayco Sportster Series 8, Few Questions

Imo, don’t get too wound up about gutting it out until you see how well or poorly you feel the truck hauls it. You already had it on an old tundra and apparently feel it works on a 1/2 ton well, or you wouldn’t have gotten a new one.
If you stuck around here, some will have you in a dually just to haul a topper on the back!
Your truck won’t care if it’s hauling around 2000lbs.
It may actually love you more for using it like a truck! Lol