I was in the same position as you. Bought a new Ford F150 last November. Also bought a New 28' Rockwood 5er at 7350 empty the same time. Thought I knew all the numbers the F150 could carry but was also mis-informed from Ford salesman on what weights my actual F150 could carry. Ride ended up sucking and bow wave from Large Prevost's passing on the left was eye opening. First time I thought I literally snapped a axle it was shaking me all over the place.
I did everything to keep the F150 since it fit in the garage and had all the bells and whistles. Did Timbrens first, then super springs, then LT tires. Still didnt handle well. Scaled in over on the max rear axle by 200# and over Max vehicle weight by 400# and also over on Payload by 400#. Minor weight infractions but still over none the less.
So I bit the bullet and traded the F150 in on a New F350 Diesel. Then traded the 28' Rockwood in (we settled on the Rockwood due to the F150 weight limits) on what we initially wanted which was a Jayco 28.5' 5er.
Lost 18K in the entire transaction from what we would have initially paid for the second set up. I consider it a learning curve. But now I have all the power I need and I am safe in every aspect and way underweight.
IMO a half ton pulling those kind of weights is not a good idea from my own experiences. I went the first way to save money on gas. The F150 Eco got 18 MPG average (6000 miles of ownership) and 8-9 MPG while towing. My F350 Diesel get 18 MPG on average and 12 MPG towing. So i would have been better off with the F350 from the get go. Only down side is it now doesnt fit in the garage any more.