Dennis,
I don't think "strongly consider" is enough of a commitment on your part. If you read the posts from those who actually haul the larger Ranger tugs, it's unanimous. They say, "Do NOT attempt to tow an R-27 with an F-150." I add my voice to that swelling chorus.
Having put 25,000 miles on my Ford F-350 while towing an R-25 all over the West, I can say that there were moments on the road when I blessed every single ounce of Brute Strength the F-350 had, and was glad I listened to the fleet manager for a construction company, in San Francisco, when he made me swear to get no less than an F-350.
As far as I could surmise, the only diferrence between an F-250 and F-350 is the leaf springs on the rear axle. In other words, the engine (diesel) and transmission are the same, the cab is the same, they just beef up the capacity to haul even heavier loads than the F-250 in the suspension, which, after all, whips your boat and trailer around the curves. I believe this applies to the 2500 vs 3500 comparisons in GM and Dodge as well, but I could be wrong there.
Check on the price difference between an F-350 and F-250, you'll see it's slim to none.
Finally, check on the Rated Towing Capacity of the towing frame itself, that is bolted onto the truck frame. I found out that my F-350, sitting on a Ford dealer's lot, had a factory towing frame included which, upon closer inspection after my purchase, I found was only rated for 7500 lbs. This, on a truck rated for 13,000 lbs towing !!! I paid for an after-market frame rated at 13,000 lbs before I ever towed my boat.
Yes, the diesel engine adds about $ 5000 to the price over a gas V-8, but again, the uphill towing torque of a diesel simply blows away a gas engine, even if you forget the better fuel economy diffrences.
When you're on the road, your whole R-27 investment is at risk if your towing vehicle fails in the passing lane, or can't control a potential jackknife situation because the frame and towing apparatus is not strong enough. Better buy a brute pickup, and drive along feeling safe and secure, not scared..........Charles