With a touring bike you want your components to be bombproof. A lot of people tour with bar-end shifters, and the like. Drop bars are a plus, but not a requirement. You don't want suspension of any bike, and steel is good.

that windsor tourist looks solid, but out of your price range. You also have to think about getting racks, panniers, fenders, to add too.

You might be able to find an older steel roadbike for cheap, and buy fenders and stuff to add. I can't quite see that coming in at $400, but it's possible if you have connections.