Hi Pat. Well, it WAS pretty scary, especially considering I've never done anything like this before and the Shays are a bit complicated. And I started out knowing little more about them than how pretty they are.
But having put most of the 2-truck together, along with making some modifications designed to make it run better, I've gotten pretty familiar with how to reverse the process as well. The MDC Shay Handbook by Jeff Johnston is a huge help, with all it's really clear photos, drawings, and instructions. Hopefully you can find good resources like that for whatever you have in mind.
I think the trick to doing any project like this is just start somewhere and take it step by step from there. Don't worry too much about whether it'll get back together or not or you may never start! Take lots of pictures or make diagrams so you don't forget where things went. Besides, I bet somebody here could help if you got stuck. Do you have a project in mind?