Hey y'all

I just moved to Brooklyn and recently grabbed this Miyata 310 off of Craigslist. It's a tad beat up, but seems to pretty ride nicely. I'm thinking about trying to strip it and convert it into s a single speed (seeing as how it is pretty flat here). I've always wanted to build out a conversion and just like the idea of simplicity. I have been reading quite a lot about how to convert my bike, and it doesn't seem to hard. Some help never hurts though!

I guess to begin I'm going to try to just strip and clean the bike. It has horizontal drops so that's definitely a plus. I believe the components are Shimano RX100.

I know that I'll need a Shimano Conversion Kit (Cog/Spacers/Lockring). I found one on amazon for $15 that seems to have pretty good reviews.

Here is where I have some questions. Would it make sense to keep my current crankset and just remove the larger gear? Would I be able to get an ideal gear ratio, or would it be more practical to purchase a new single speed specific crank set?

Aside from that I will likely purchase a new chain, brake caliper/lever, and change out my handlebars and pedals. Also the cups/nuts of the headset are pretty rusted out, and I would like to replace them. Any recommendations on where to find these parts?

I guess I'm mostly confused about converting my back tire, and whether or not I should change out my crankset. I plan to do a bit more reading about gear ratio, as I will have to figure out what ratio I want to ride. I do have a friend that is a bit of a geared that I plan to ask for some help, and also plan on making a few trips to my local bike CO-OP (seeing as I don't have any tools).

I have some pictures that I can upload, but can't because I'm a new member. Sorry about the long post, but any help or advice is really appreciated.

Thanks!