Colsons are pretty valuable. Balloon tire cycle collectors rate them above many other makes. Original parts are going to be tough to find, and expensive.

I'd keep it as a rider and enjoy it as it is. If you bring it back to original condition with original parts, you'll have a lot of money invested in it and you won't want to ride it.

Vin - Menotomy Vintage Bicycles, Inc.
http://OldRoads.com