If the F250 you are looking at has the camper package, the suspension is the same as the F350 but uses a 2" shorter rear axle block. The rest of the components are the same between trucks except for possibly the wheels. If you are following the door label ratings, you will most likely be over GVWR on the F250 due to pin weight yet fine on the F350.
Take a look at the the changes between the 2015 and 2014 model year trucks to determine whether the savings of the 2014 are worth changes you would get in the newer model truck. I recently bought a new truck and waited for the 2015 specifications before deciding which truck make and year I was going purchase.
This time around I was looking at class 5 trucks and chose the Ram. Ten years ago when i was looking at class 2 trucks, I chose Ford. I suggest you try all three makes with an open mind - I bet there will be one that you eliminate immediately because it does not fit you and then you will be able to pair off the remaining two to get the best price and fit for your needs.