Derek,
I can't help you with any parts, used or otherwise. You might reach out to forum member redsqwrl. He's a heck of a nice guy, and lives in your neck of the woods. In terms of terminology, the large diameter wheels at the bottom of the carriers are called idler wheels, and the small diameter wheels on either side of the drive sprockets are called damper wheels.
New ones of both sizes would be available from the Tucker factory (1-866-snocat1). I've had excellent experiences ordering parts from Tucker. They ship parts promptly, and they don't treat shipping charges as a profit center; meaning shipping charges are reasonable. Parts prices though are expensive. But I'll also throw out Tucker is in Oregon, a state without a sales tax. They don't have a physical presence in Wisconsin, so I think you'd at least save the sales tax on your purchase. If your existing idler wheel castings are in good condition you could save money by having them recovered. I don't know if anyone is recovering damper wheels, but I discussed recovering idler wheels last fall in this thread:
http://www.forumsforums.com/3_9/showthread.php?t=80818
As far as removing damper wheels, in theory you could remove the cotter pin and castle nut on the front, then remove the bolt on the rear of the carrier holding the spindle to the spindle tube, and then hold the damper wheel while simultaneously pushing the spindle out through the spindle tube. I say "in theory" because the spindles tend to "develop an attitude", and can be a significant pain in the butt to remove.
As is so often the case, having the right tool makes the job a lot faster and easier. In this case that would be a Tucker track jack, which is used to compress the track so the bolts holding the belt lacing together can be removed. When Tucker delivered the machines they came with one, but the track jacks seldom stay with the machines as they change ownership. You can buy them new from Tucker, but the price will at a minimum raise your eyebrows.
I have never owned, or worked on, a 1300 series machine, but my gut feeling is even with the front drive sprocket out of the way you won't be able to slide the damper wheel past the grouser bar wheel guides without loosening the track tension considerably. Splitting the track may seem the hard way, but it may be quicker in the long run.
Good Luck!
