The dry weight is the weight that in theory the trailer weighed when it left the factory. Adding items like a battery or water to the fresh water tank or food or clothes and other travel gear will increase that weight. Safest is to add 1000 lbs. to the dry weight to determine the requirements for a tow vehicle.
What is almost always overlooked is the difference in towing capacity that results from the rear end gears for the vehicle. GM rates its 3.73 equipped vehicles 25% higher than those with 3.41 gears and it rates those with 4.10 gears 25% higher than those with 3.73 gears for its gas engine powered vehicles.
For towing I would get a vehicle with 4.10 gears if possible and no higher than 3.73 gears. This puts less stress on the engine and the transmission and works better for towing. It can also help fuel economy overall with the engine spending more time in its peak power band while towing.
All the manufacturers have downloadable PDF towing guides and these are revised each year. They provide towing capacity, loads where a weight distributing hitch is recommended or required, and other useful information and all it takes is a couple minutes of your time to download.
Tow package options are one of the only good deals you can get with the purchase of a vehicle. Usually the radiator, alternator, and transmission cooler are upgraded and the factory installs a hitch and trailer wiring. It is a bargain compared to getting this done later.
7500 lbs. is on the border between a 1/2 ton and 3/4 ton pickup. The newer trucks often have stronger frames and better brakes and are more adept than ones made 10 years ago at towing. The 3/4 ton trucks will have a harder ride and weigh a lot more than the 1/2 ton pickups and provide worse fuel economy. For a 10,000 lb. load it is an obvious decision to go with the 3/4 ton truck but not for a trailer load under 8,000 lbs.
If I wanted an economical rig I would plan on buying a 1/2 ton pickup and get one rated for 7500 lbs. or more towing capacity and then buy a trailer with a dry weight of less than 5,000 lbs. and able to carry up to 1000 lbs. of gear and provisions and fresh water, etc.