Never owned the Deerslayer model but:
presuming the rifled barrel isn't "pinned" it is easy to remove the barrel on an Ithaca pump and you can clean it from the chamber end.
If it is pinned, you can carefully clean from the muzzle end with a brush and then patches. The worry about cleaning a std. rifle from the muzzle end and the reason for bore guides, is to protect the "crown" of the barrel. Not sure if a rifled shotgun barrel actually has a crown.