James: If I recall, the Explorer is a mid '90s 24 footer weighing about 3400 lbs. Not sure you will find too many with with an F250, but I can offer what I get on a 2005 Journey. My boat is 24'9" with an 8'6" beam. Dry weight is about 4100 lbs. The F250 gets me about 27 mph at 4,000 rpm and I can get 3.0 mpg on flat calm water. So I'm burning something less than 10 gph on calm days with a full tank of fuel, but otherwise lightly loaded.
At trolling speed I think I'm burning about 1.5 gph.
Hope this helps.
By the way, I have 1038 hours on my F250 and it has been flawless.
Rob