If this was restricted to firearms, I too would be after some original Hawken rifles, colt pistols, sharps rifles, original Winchester lever action rifles, Spencer carbines, just the things that on today's market sell for the very top dollar and sell quickly. Purchase enough that you could keep one for yourself and then sell the others. You'd be wealthy!
And considering the value of a dollar back then compared to today, you'd have a huge amount of firearms that you'd be hauling back. For instance, I read somewhere that the original Winchester Model 76 rifle sold new for $32.00 . I watched a show the other day where a person had an original in mint condition and wanted $10,000.00 for it. Whether he got that or not who knows. But think of the investment opportunities you would have with that kind of merchandise.
This is a very hard question because there are so many rifles I would want to get. And things I would want to see! Think of all you could see and learn.