[dsraven]

nice looking start, sorry to hear the reason for the aquisition.
before you do much with the truck you may want to check the frame for square, straightness and sag. block it up, do a corner to corner dimension, both ways, then compare the results. that will give the squareness check. for straightness what I usually do is mark each cross memebr at it's midway point from side to side, then run a stringline or a laser from front to rear and see how many of those markes line up. a stringline can also be used for checking the sag, use some wood blocks to space the string off the frame at the front and rear then use a same sized block to check along the frame to ensure the space is the same on the straight parts.
there is a free download for an assembly manual on the tri5 site. just google

55-59 chevy truck factory assembly manual

and pick the tri5 site. maybe download it to your computer or onto a thumb drive so you have it, you never know how long these things stay on the net. this will have frame drawings and drawings of how the factory put the truck together, where spot welds are located, etc etc
if doing a front clip one thing to know before you start is that the ride height desired needs to be firgured out before you cut the frame and set the front axle position. this is because the front fenders on these trucks have a tapered wheel opening, on the rear of the opening, and as the truck is lowered down over the wheels (like most guys want-a little lower than the stock height. some like a lot lower...) it makes the tires look like they are being stuffed into the rear of the wheel opening. the more drop you build in, the more the axle centerline needs to be moved forward to make it look right
one thing I would suggest is to figure out what you want in the end and then do everything you do towards that end. try not to change your mind midstream because it takes you down a rabbit trail that usually means you need to redo something already done, it will be something that is gonna really challenge you abilities so it may stall the build, or it is gonna cost a bunch more money to finish. it's one reason why builds get sold part way through after sitting in the shop for a long while untouched.
start with building a good strong foundation that will handle the intended use. then worry about the bodywork, stereo systems and other peripherals. I have seen a lot of guys who have thousands of dollars in wheels, tires, steroes, seats, exhaust parts,etc etc, just sitting there in the way and the frame isn't even done yet.
figure out what you have to work with mechanically, rear axle, springs, frame,etc etc, figure out what you have to work with body wise, cab mounts, cab eyebrow rust, cab corners, hinge pillars, floor panels, fender patches, headlight patches,etc etc. write it down so you don't have to go sliding back under it, take pics of stuff as you go so you can just look it up when you need to know a detail, then dedide what you want to do for suspension, what you want to do for an engine and trans, steering column, etc. sometimes you can be money ahead by buying a wreck from the insurance write off lot. it will have the engine/trans combo. wiring and computer, seats, steering column etc etc. you can sell off body parts from it to help pay for it etc. you gotta have a place to put it though.
I like your idea of a driver that will get you around without dragging bottom ort worry about potholes etc. you need that if you don't live in a city with pavement everywhere. also, being able to use the box to put something in when you want.
post up some pics as you go. we all like to see what others are working on. you will also get lots of suggestions and help if you post pics. sometimes you don't realize you may have a problem but somebody else will see a pic and point out a potential issue.
welcome to the club