I understand your concern. We had the same situation almost. Were thinking about getting a small fifth wheel which put us in f250 category. We could have gone with the max tow / max payload F150 with special order. The price of the max tow / and f250 were about the same.
We really like the ecoboost and looked at a lot of TT's / FW. We ended up deciding on a 2500rl Grand Design. I think the weight on the TT with gas is 5600 +/-. Max loaded weight is 7500+/-, very similar to what you are talking about. We purchased a new ecoboost with max tow pkg but not max payload. Our payload is 1780 also. I feel very comfortable with this package. There are only two of us and we usually load about 1000lbs in the TT.
We are leaving very soon for our Florida trip. Still getting the TT set up. We did tow it 5 hours empty to get home from the dealer. I think it will tow very similar to our previous TT which was about 5100 lbs empty. Our 2013 ecoboost without max tow and less payload than the new one handled it fine.
I will say we are at the max TT for my comfort to tow. The specs say it will tow more but payload will get you. btw most TT dealers will tell you you can tow a 10000 lb TT or fifth wheel with any ecoboost. Of course they don't have to ride with you.
