Muzzeloaders due to their design (fixed breech) tend to have varying degrees of wear/corrosion that can't be easily detected. exterior appearances may not be telling of what has happened inside.
Consequently the Gun Traders Guide doesn't go into putting values on such beasts.
The best you can do is visit an online auction site, like Gunbroker.com or Gunsamerica and see what people are bidding/paying for guns like yours.
Cherokees and Senecas do have a minor cult following, and perfect examples may bring a decent penny. Used models with some wear/dings........might do well due to colelctors wanting a "shooter".
I myself run an older model, limited run TC, and hunt with it. In VVG shape with a few tiny marks, it's worth about twice what I paid for it new (according to current bids seen on the web- but I aint sellin' it ).