Originally Posted by blwnsmoke
I get 6,300 miles on a tank of DEF.
You won't have 3850 payload.. it will be about 3,100 payload. Then add your family, hitch and any other gear in the truck. Then take your pinweight and add a few hundred more to that since you will have gear in the 5th basement and front room.
If syou are going to have your dealer do all the services, I'd recommend buying the maintenance plan. It is cheaper then paying for each service separately and my contact will sell them for $100 over cost.
3100 may be a little low. My 2016 F350 Lariat has a payload of 3573 lbs. a platinum may be slightly less because it has a few bells and whistles my Lariat does not, but it's still an awesome truck. You are correct about subtracting passengers and gear from the payload. Also back out the weight of tools and whatever hitch you choose, which is another reason I like the B&W turnoverball in the truck, and a Goosebox on the fiver. Solves a lot of issues.
You will really enjoy the truck.
With 30,000 miles on it, you have 6,000 miles of bumper to bumper remaining. You might ask the dealer to pull the maintenance records before committing. Just to see if anything has happened. Not 100% but still good info.
The def is no big deal as long as no one has put def in the diesel tank. I buy my def at Sams Club where it is a little over $10 per 2.5 gal. The truck will use a lot more def when towing. The DIC will give you a warning when there is 800 miles worth of def remaining. Ford really should have a gauge showing def levels.