Sounds like you are on the right track, and I assume that you already have everything that you NEED. I assume, since you fish some, that you have a knife laying around somewhere. Give it a real good edge, and it'll be fine. You can sit on the ground around a tree, or vegetation, as has been said, and save that money you would've spent on a ground blind. And, yes, a deer cart makes things easier, but I have never used one. If I get tired while hauling a critter out of the woods, I just take a break. No, hauling a big deer out of a holler ain't much fun, but it's definitely worth it.

If there was one thing that I would add to what you have, it would be a bone saw. Being able to cut the breastbone up to the legs, or so, makes field dressing MUCH easier.

The first thing that I would start saving money for would be a good pair of binoculars. Don't buy cheapos...save up for some decent ones.

This is all MY opinion, and you have to decide what you think is best. Do what you think is best, get out there with your son, and have fun! That's what's most important.