You will get hot and sweaty, and there is no way to say this politely: smear some lube (many to chose from in bike shop or good old Vaseline which lasts longer but doesn't wash as easily) in your crotch and buttocks to prevent heat rash as well as chafing. Nothing ruins a tour like sores. Cycling clothes are beneficial but many people tour without them. Don't sweat the decisions about shoes and pedals now. Just get a bike and make sure it works! Finally, read the articles on touring on this website. Good luck!