I have a 2001 Chev. Silverado 2500 HD 4x4, long box, extended cab, 6 liter Vortec, 5 speed overdrive manual transmission with 155,000. K on it. They are amazing motors, very reliable and always jumps to life at the touch of the key, - no cranking ever. The truck also came with a large, walk on it, bush-guard bumper with skid plate,10000lb Warn winch and a factory duel battery system with isolator. With a winch and/or a camper I would think duel battery is a must have.
You asked about seating. It has a cheater seat in the front between the main seats (the center console folds back and turns into the padded back for the seat) and a full bench in the back so it will seat 6 (sort of) but but four or five would be more practical, especially for distance. Not a lot of leg room in the back if you are very tall and the front seats are full back.
I have found I seldom use first gear as it is so low that you get very little speed out of it. 2nd gear is essentially first gear, even up inclines, unless they are steep. Put it in bull low 4x4 and first gear and all it is good for is pulling stumps, getting going hauling a heavy boat up a steep slippery ramp and climbing over boulders. Like most good truck motors, the Vortec, seems to be optimized for torque not hp but it certainly has enough hp. The truck was ordered as a work truck fleet vehicle which means it has the stuff you want for the bush, like skid plates under things like the transfer case, huge built in fuel tank and duel batteries, but none of the bells and whistles that dealers rely on to make them a fortune repairing.
There are no power heated seats, mirrors, door-locks and windows etc. The only thing I miss is power windows, as the truck is so wide that if there is no passenger to do it and you want to hand crank the window up, you can’t do it from the driver seat on the go.
The only other negative is that it is not a fun truck to drive in the big city. It is extremely long and wide and no fun at all to squeeze into tiny parking spots designed for little cars. I am also happy when I get on the ferry without them noticing the huge bumper and long box etc. and don’t come out to measure me for possibly being over length. Fuel economy is not great and it costs about $95.00 of regular to go from Victoria to Campbell river and drive around a little for a couple of days. The interesting thing is that fuel economy does not seem to get worse if you are hauling or pulling a lot of weight. Hope this helps if you are thinking about going Chevy non-diesel.