This is a really nice find for 10 bucks! Miyatas were always great but they changed around the quality of the models alot. By 1986 even the lower end models were pretty top notch bikes.
From the top tube font, it looks like it's a 1986, the same year as my 210. Based on the specs from miyata catalogs, it looks like this is probably the non-touring equivalent of the 210 for this year. They should both have triple butted frame tubes and serviceable shimano light-action components.
Like ColonelJLloyd mentioned, a new chain is worth the investment (<10 for a nice KMC) and maybe a new freewheel (moot point if you're getting new wheels). It will probably ride like or better than a brand new bike with a new 700c wheelset!