I think it's really helpful to have general book with lots of pictures from your country. It should have general details about different aspects of your country (demographics, tourism, different industries, tourism attractions, school system, etc) and include lots of pictures. I then scan in the pictures to a computer and print them to transparencies and use the info to make general slides that I can use at a lot of my presentations.
Bring lots of slides/pictures, other visuals (e.g. map), music, traditional dress, etc! People usually don't just want to hear you speak - it's much better if you have lots of pictures to show, have traditional clothing and interesting display items (although I hardly ever get asked to bring display items with me, they are useful for booths and such). Also, people really like it when you play some music, even if only for a minute - demonstrating a simple dance along with the music usually also works great. I'm glad I took the time to learn a simple Bulgarian dance.
Local transport - around Corvallis, you're probably alright with a bike, although there are some buses. There are also buses to Albany and Portland.