Biggest thing to look for is the stator condition. There are three yellow wires to the left of the battery that run through a connector. Check to see that it is in good condition or that the connector has been removed and the wires soldered together. That won't guarantee that the stator is good, but it's a good start. If you have access to a voltmeter, test the output of the stator by checking the voltage at the battery, with it running. It should be at ~14.2 volts.
I always recommend that people look for a 1500 for their first wing. They just were made for 13 years and there is a bonus of parts available. Having said that, there are many 1200's out there that get plenty of miles on and people are happy with theirs.
I highly recommend the GWRRA groups (Goldwing Road Riders Association) to find folks who ride wings in your area. When you attend chapter meetings you will find friendly folks that ride the same motorcycle you do, and like the members of this forum, they know their motorcycle.
You can find a local chapter by going their website
Welcome to GWOF from Down Under. I am a bit different to most people and am not scared to spend what ever it takes to make it reliable. But thats just me. And then I get out there and ride it like a new bike. Every now and then you may have a break down. And that is just life. Eric