I concur with the non-original fork, Miyata did not mix caliper and cantilever brakes on these models. Replacement forks are a pretty relialbe indicator of a front end crash, so there's a good chance of main triangle damage too. If you're planning to buy, look it over well for paint damage just behinf the head lugs.

Whiloe I have not personally expreienced any problems with Miyata's APA bonded frames, some of the European members have reported problems.