Honestly, as much as it sucks, it doesnt sound like the guy was out to screw you. If he was he would have met you in a shady parking lot with no way to recontact him or future accountability. He met you at his work, so you knew where to find him. Usually people who are knowingly trying to screw people, dont provide their home or work address, for fear of a rock coming through their front window once the buyer realizes they have been had. It sounds like an honest mistake.
I also dont think grumbling about the distance you had to drive to have the bearing pressed is his fault. Was he supposed to come pick it up and then re-hand deliver it? That seems like you might be expecting a bit much if thats what you were anticipating. His shop press is located where its located, so its not like he could bring the press to you.
At the end of the day, you got bearings pressed and a $450 kit for $238 ($200 + the $38 in extra needed parts), as with any low priced used part sale, buyer beware. He probably feels like "i already pressed the bearings in for you as a favor, I am trying to be a nice guy, and now you are complaining about $30 bucks in hardware on a kit thats already discounted $250??" where you are seeing it as "it was sold to me as this, so thats what I should get". I think its easy to see both points of view.
I don't get the impression he was trying to screw you, I think he just reached a point where he could no longer help. I always remind myself, "is the deal worth it if something in the kit fails to work". Treat every transaction like you will never see the guy again. Sometimes its just better to buy new, as a private party is not a store, they do not have inventory, real accountability, refunds or warranties.
If someone outright lies to me (example i bought some wheels that i were told "just came off a 72 challenger"....they ended up being the totally wrong bolt pattern, the guy obviously lied), i have a problem with that, even though in that example i gave, i still should have double checked. If there is an honest mistake (example: full set of valve cover bolts that ends up being one short) that could have been prevented if i took the time to investigate a little further, so its pretty much on me.
Part of the savings in buying used parts is that you are taking on some risk in exchange for a lower price.
I personally feel very sympathetic for your situation, as I have been there too on more than one occasion. I hope it all gets worked out. All you can do is maintain your integrity the next time you are in the "seller" position, and help keep Mopar enthusiasts in a good light. I know i try my very hardest to be as honest and work as hard as possible to be fair when dealing with others. Karma is a b!tch, and I would never want to tarnish my own name or reputation over a few dollars, as in the end, all you really have is your word, and your actions.
Again, I am sorry to hear about the difficulties you had to face with all of this.