I'm trying to upload the simpler version of Back Up and Push (without all the crazy double stops) but am having some technical difficulties. I should have it for you this weekend though so you can get started learning it. Once the tune is learned, we can add in some of the less troublesome double stops to make it sound more Bluegrassy!
I would make sure to learn the cross shuffle first. (It's the second half of the tune with all the 16th notes). Get the pattern by practicing on open strings. Eventually the pattern will be played very fast, so if your bow knows what to do at a fast speed, it'll be a lot easier to play.
Keep a lookout for the music here...