The regular cab long bed S-10 trucks are very close to the wheelbase for the 47-54 1/2 ton trucks.
Our kit is meant for 1/2 ton trucks, but we've had a couple guys who started with 3/4 and 1 ton trucks and just shortened up or replaced their bed with a 1/2 ton one, when they got to that point. Depends on what your Vision is of how you want the truck to turn out.
Here's a 48 that started as a 3/4 Ton Regarding the "whole track width issue" do some research on your own and decide how you feel about it. Some people don't like having to use wheel spacers on the front. In my case I know 4X4 guys who have used them for years, and circle track guys who have used them and it doesn't bother me personally. These guys beat the heck out of whatever they are driving.
The kit we provide is meant to not just swap the S-10 chassis but also includes parts to move over the brake system (including the swing pedal and brake booster), accelerator pedal, the wiring harness, steering column, and we include a trans cross member and motor mounts for a V6 or V8. We also include front bumper brackets and wheelbase correctors to shift the wheelbase even closer to the stock 47-54 1/2 ton truck.
Going either route, I wouldn't plan on it being a weekend deal. With a couple guys to help, and a really good game plan it can be done but it really depends on your level of experience with this type of work. I usually recommend starting with your old truck before you buy anything. Pull the front fenders and the bed and start looking seriously at your cab. The floor and cowl are usually the worst spots and if your doing a chassis swap or just an IFS to make the truck more drive able if the cab is rocking on it's mounts it's not going to be safe. The corners are usually bad too but they don't really compromise safety. If you want to maintain the "Patina" of the truck this stuff can be fixed with a minimal of disruption to that. Once that's all squared away then go ahead and make whatever purchase you decide and move forward. I've seen too many guys spend big money up front on parts and kits then get mired in body work and repairs later and eventually give up and have a project they are upside down in to get rid of.
Mongo