I now have everything I need for successful completion of this project. I’ve been buying (and returning) lots of random components but now have all the parts I need. I’d found a large variety of different colored bike chain and bought many different ones to see which one fits my aesthetic best, and I’ve decided to go with the gold (see below) and send back all the brown options.
I’m actually using derailleur sprockets to make the chain rotate, based on only their price and mount-ability. They can easily press fit onto a shaft or be bolted onto hardware, where normal sprockets have a difficult bore to mate with. I’m slightly worried about their structural characteristics, but with the tension I’m going to have it shouldn’t really be a problem.
I have my free wheel as well, again with a brass finish for the aesthetic.
I went to the lumberyard and found some really pretty 2×1 wood sticks, which I’ve started to sand down to make the keys. It isn’t an actual dark wood (it’s pine), although I bought some dark walnut stain that should give me the same effect. I went with the pine because it had a really nice visible grain that will give a great old wood aesthetic. I’ve cut the keys down, and started to sand them, although it’s a time consuming process so I haven’t finished these yet.