Trying to locate Japanese penfriend

I will visit Japan during the period 26 Sept 2014 to 10 Oct 2014. I will consider my trip a great success if I could meet my penfriend of the past with whom I had last letter correspondence in 1980! She was staying in Nagoya at that time with her parents and studying. She must be 54 now.

I have all her letters and photos plus her postal address. Should I write a letter to her old address of 34 years ago? Or is there any other way I can nudge her? I know she will be interested to meet me during my visit.

I think you should do.
But I guess it's hard to catch up the way back 34 years ago unless you both are school class mates.
The address may still valid or invalid. The most Japanese residents tend to stay in one place longer(sometimes more than 100 years). If it's still valid, you can't expect a bright response always.