Welcome to the site, Wendell. It's good to do some research ahead of time. Not sure what you mean by a swb, if that is wheelbase, all 3100s were 116". Mileage can be anywhere from 13 to over 20, depending on how you set it up. Lots of parts suppliers around, just click on 'links' at the top of the page.
Good luck in your search.
Leo
