i wish i could be more helpful but i just remember arriving in the evening and just catching the lodging assistance desk still open. it was rather easy to find an inexpensive ryokan and call to reserve the room, but to leave the train station on foot and find the place was beyond my abilities. as it was late and i was lost, the only establishment open was a sake bar. in spite of the interruption, one person was found who both knew the address and could speak to me in enough english to tell me i'd never get there alone. so he walked me the rest of the way.
long story short - the people of yamagata-shi are very kind to foreigners, and, take a taxi.
i did very much enjoy my two days spent there.