The difference in cost of an F250 vs an F350 is about $1,000 or less. Compared to the total price of the trucks that is minimal.
We have a 2012 F350 FX4 and, yes, it is pretty high up. But with the wide running boards, standard I think on the King Ranch, and grab handles even the DW at 5'-4" has no problem getting in it. Two wheel drive trucks are shorter.
If you are confident you will never go heavier or larger, then go with the F250 if it seems to fit better. If there is any doubt in your mind that you might someday move up a notch or two, then go with the F350.