I have a K1500 Suburban, a good friend of mine had a supercharged Tacoma, we both had 4,000lb boats four years ago. Supercharged Tacoma had way more horsepower and torque than my overweight Suburban. However every time we took out boats more than 50 miles I ended up with 7 people in the Sub, completely loaded with all the gear, still getting 10.5mpg while my buddy was in the empty Taco with his wife and an empty boat. I could not keep up with him in a straight line but he barely made it up the hills I cruised up. He also got 7-9mpg pulling his boat.
After several trips to California and Lake Powell he fried his tranny, rebuilt it and now drives a 3500 Cummins. I sold the little boat two years ago and now have a 7,500lbs boat dry that we regularly tow to California and Lake Powell. 5.3 vortec with 3.73 gears and 4L60e tranny has 250k miles and still going strong.
Supercharger might be the answer to your power needs however you should be expecting to rebuild the tranny pretty soon. Another option is to get lower gears, that would give you the feel of more power but cut back on the truck's top end. As someone said earlier that that 1-2 mpg penalty is way worth it with all the room and peace of mind you get in a 1/2 ton V8.
Good luck
