Welcome to this board. I agree with the conditions related to sponsorship but people here could probably help. The more info and accessories you have the higher it will push the value. Your description is essentially correct. That is the only carriage in existence and probably the only limber. Having the original wood is really special. From now on don't do anything to it without professional advice. Preservation is the key. It might also be time to do a survery of all the items Hugh Coleman brought back. Check throughout the family. Any original documentation or diary entries about it would be invaluable. The question is what was brought back in the limber. There might have also been ammo chests that attached to the cannon. Any parts or tools for it would be a major plus. If you're not sure what it is feel free to post pictures here or on your site and solicit opinions.
Any original projectiles would be very, very valuable but also potentially dangerous. If you find some, don't touch them unless you know they were demilled. The Artilleryman recently ran a couple of articles about demilling Civil War ordnance. If you find shells, don't call the bomb squad but see about getting them safely salvaged. Sights, and implements or parts of them would realy add to the value of it all.
Steve
