Thanks for your insight! I'm getting the impression from all of you that "less is more", for the most part. I pretty much overdid it with my list. Maybe I still bring all that stuff, but leave much of it in my car and only get it if I need it.
I carry cash, a magnifier and a laptop with a ten inch screen. I have want lists, and about 17 to 20 different refence books on the laptop in digital form. (and I add more reference books as I have the chance.) That lets me carry around the equivalent of 60 to 80 pounds of reference books with me. The laptop weighs around 2 pounds.
I have almost never had problems withhthem accepting checks. In some cases I have had them tell me if I used a check I had to pay sales tax (not a problem) and in a couple of cases where they were reluctant I offered to include extra for shipping and they could send the coin once the check cleared. That solved that problem.
A lot of the dealers at my local/regional show take credit, but either explicitly add a surcharge (usually 3%), or are less inclined to negotiate. Over the last ten years or so most of my business at shows has been selling, usually junk silver that I got below spot. Most dealers will pay cash up to a couple of thousand dollars; beyond that, they start to prefer writing checks, if only to keep from running out of cash themselves. NC exempted coins and PMs from sales tax a few years back, so that aspect of tax-dodging isn't a factor here. (Reporting profits as income is still between you, your conscience, and the IRS.)
Hey, I picked one who completely shares my own opinions on finance. I used to be a pretty smart guy, sometimes.