My 2010 F150 has been a good truck for me and my small farm, and has been more than capable of dealing with any towing I have thrown at it (I have a 2H gooseneck with front ramp, so not a small trailer). I can haul it loaded and stop easily and quickly (though I try not to do the latter with horses!) The truck is rated to 9600 lbs and with 2 horses and stuff my trailer is around 7k.
I would recommend the full size bed. On trips to the feed store I would like to be able to haul more bags of shavings and Iād also like to be able to get longer boards home easily. a 12ā board doesnāt fit in a 5.5 bed.
I have a 2013 with the 3.5L EcoBoost. I selected the packages and configurations that maximized its usefulness as a towing vehicle (156" wheelbase, max towing package, HD payload package, 4x4, etc.), and my specs do not reflect the above at all. I have a towing capacity of 11,000#, and it tows my steel gooseneck with ease.
I knew what trailer I was going to purchase when I was buying my truck, so I worked backwards: I knew the trailerās specs, so I figured out what the minimums I needed for GVWR, towing capacity, GCVWR, payload, wheelbase, 4x4 etc. were. Then I looked at all of the available options, and found that I could either buy an F150 configured as above, or a 3/4 tonne.
There were other half tons that had more than enough towing capacity but were more than maxed out on other specs. I would strongly encourage anyone looking at a truck to look at more than just the towing capacity. You often surpass the tongue weight or gross weight ratings before ever getting close to the tow rating. I actually made an Excel model that friends used when buying their rigs. You can input prospective truck and trailer specs and figure out if you have enough capacity.
A 150 is, IMO, quite enough, but Iād certainly do a 5.0L or larger engine. I had a 2000 F150 5.4L with 7000 lb towing capacity up until two or three weeks ago. My dad bought it new, I bought it from my dad a few years ago. We have a 20 acre farm. Sure, it would have been nice to have a bit more payload capacity, but it wasnāt the end of the world. Loved that truck, I was devastated when she died. Died from a faulty alternator - we had to have the alternator replaced a little over a year ago. Apparently the new one was a bad one, as itād been putting out 18 volts for who knows how long (should be < 15) and destroyed the electrical. We junked it. Sad day.
Iād go with the 250 because like others have said, you will never regret going with more truck with more hauling capacity than if you have a truck that canāt haul what you want. If you have a 4 stall barn then Iād plan for that impulsive horse buy in the future. Personally Iāve got a 2014 250 6.7 off the lot used with only 10k miles. Walked off the lot with it decked in chrome, custom matts to catch on all the dirt/water, backup cam, spray in liner, etc. You name it & it had it minus the gooseneck hitch I later installed. I STOLE it! Still have the truck and its a work horse!
My mom had a 2013 150 that she liked. Wasnāt fully loaded but it was a work horse on the farm here in ky on 48 acres. She recently traded in for a 2014 explorer thinking it would be nice to take the dogs and ātravelā. She ended up trading that explorer (junk IMO) for a new 2018 150 fully loaded. Truck so far is extremely impressive and very similar to the 2014 250 that I have. BUT when it comes to towing, my truck will pull more weight with less wear.
If you are sticking with a 2 horse then Iād go with a 150 which has been rated the #1 truck. BUT if you want better pricing with the ability to haul heavier weights then Iād go with the 250. Just depends on your future plans and $$.