While most vehicles mentioned will do the job, the F150 with the Eco-boost engines, will work great for you. Not only do they give huge power to tow, especially in the mts, due to the turbos, but get great mileage when running empty. For your use, the 150 with 2.7 Eco, will do it all, and has been a good engine. If you think you may be moving up, after using the PUP, then the 3.5 Eco may be a better choice for your next trailer. Most people that start out with a small camper, move up in size. You may as well start out with a truck capable of pulling a 7K lb trailer up the hill.
Jerry