If you want a V6 truck, it will save you money if you buy new. On the used market, you can get a better deal on a low mileage V8 truck. Most V6 trucks are limited to rear wheel drive only, if that works for you, fine!
I'd go with the GM 4.3L V6. Most come with the 3.23 rear axle, but 3.73 was a no cost factory option for most years, even 2010 models! The V6 makes max torque at 2800rpm, versus a high HP V8 in the 4000rpm range. Even with the 3.23 axle towing 2.5K (my estimate of the weight of an open trailer and your equipment). The V6 gets similar mileage as the DOD 5.3L V8 and 6 speed transmission with 2wd (non XFE). For the $2K cost of the 5.3L V8, added maintenance such as 2 quarts more oil to change each oil and filter change, more weight on the front end which reduces handling (from what there is to begin with), and having less tech such as the displacement on demand (DOD) system will save you money on future repair bills. Having two cylinders less also means you save a few bucks during tune ups. Not to mention the base price is low for a reg cab long box when compared to a loaded V8 extended cab model that you might never use.
Having more power and interior trimmings is great, but the V6 can legally carry close to 6K and it also has the highest payload rating. If I could live with rear wheel drive through 6-7 months of winter where I live, I'd get a GM W/T 4.3L ext cab short box.
With a previous business I an Astro C/V and a Savana C/V both with the 4.3L V6. Around town mileage was in the mid teens for both vehicles. I traded the Savana in at 228,000miles (370,900kms) and it burned no oil, and went 4K between regular oil changes (no synthetics). I traded it in for a 6.0L 3500 for the extra payload and mileage plummeted to 11-12mpg in town.
Needless to say, capability has a price, and if you want more, you'll pay for it. Only you can decide if the V6 is a good fit. It's not that I don't have the capital to buy a high end V8 truck, but for me, I won't use a vehicle like that to it's full potential.
As for trailer brakes, if you're under 2K, you should be fine without any. Check with your local DOT office for mandatory regs. I believe trailer brakes have to be on if the total weight is 3.5K or over. You can still install them on your trailer if it's not already equipped. I know you won't admit it, but if you're a more aggressive driver, it would be a wise decision to add trailer brakes.