Just an FYI about the IDT: I don't know if this is true on all the Pfaffs or not but I have feet that work with the IDT engaged and some that don't. The ones that do have a little "cut out" space on the back of the foot which is where the IDT fits in when engaged. Just wanted to mention this in case you still don't have the book and try to engage the IDT but find it doesn't fit in. Might just be a wrong foot.
Sounds like you and your wife are going to have fun with the machine and the creating. So great that you got this and helped out your sister at the same time.
edited: Check out this youtube about the IDT. It might just help.
https://www.youtube.com/watch?v=ijQzDYfHeEs