Hey this might help you envision things. It is an image google search on the term Pulley system

I know this may not be what you are looking for but i thought you might want to download for another project.
http://155.69.254.10/users/risc/Pub/Conf/04-c-hmm-puppet-d.pdf

Billy D.

Its a neat idea but a bit above my head sorry .

Scaffolding normally is made of pipes that are fitted together and screwed.  There are then "plateforms" that lay across the pipes.  Unless you are going to have the puppet inside the scaffolding you need to figure out a way to get an overhang to the side of it that you can attach the pulleys to.  Perhaps some 2x4s layed on the top platform and then secured with "C" clamps.  The scaffolding is most likely rented so you may not be able to screw into or through it.  "C" clamps are a good way to attach things to it.

I'm not entirely sure scaffolding is right; it's just the term the curator used. I think she probably means something more like a truss, used in doing lighting rigs. Either way, I'm in the middle of getting this info from her which will help immensely.

How long is this going to be displayed?  If it is only a month or two install then I bet you can get away without using pulleys. Get some "I" bolts to run your rope through.  You can drill a hole through the 2x4 slide the bolt in and then secure it with the nut.  There is no way that bolt can come out.  Ok I guess the nut could work loose over a long period of time but you understand.   You could use "I" bolts in your puppet as well to attach the rope to if you wanted.

The puppets will be up from mid-Sept through til April. The idea is that this will be an interactive display; I'm not sure if bolts will hold up over that time and with kids pulling on them every day? (I mentioned pulleys because that's what was used in Korea - the pic above - and just though it would be easier to model everything on that since I know it works)

A chat with a handy man is definitely needed!

Thanks Billy, bookmarked the pdf for later reading

You should be able to use my suggestions with a lighting truss also.  The key points are the use of a 2x4 with eye bolts through them that you can then use as your guide or attach pulleys to. You might actually be able to find a pulley that has the bolt on it so you can skip the eye bolt.  Get yourself some "C" clamps and you should be set. Also even with the truss if you can lay your 2x4 (I assume you realize you would be cutting them to size.) across a support.  It is more secure to lay the board "on something" instead of suspending it from the truss.