Terry,
The above two posts give good tips on where to stay. Pick up a copy of the Chama yard walking tour brochure, either from any "Friends of the C&TS" people on site, at the station, or at the above mentioned "Shops." I'm sure Roger has copies available. Then go where you please, just watch out for active equipment moves. Don't enter the engine house without permission, but I've always found someone willing to walk me through.
If you go to the Friends web site, they will have a schedule of work sessions for next year. You may find that you are there during one, and there will be lots of folks willing to talk to you and show you around then.
During the George Bartholomew era, they sold cab rides, but the RGRPC has stopped the practice and has a strict no cab riders policy in place. Maybe that will change someday, but don't plan on it for next year.
Where in Michigan are you from? If you are near Flint, consider volunteering and working on the Huckleberry RR. You can get a cab ride in their 4-6-0, just for the asking, and when the K-27 #464 comes back out of the shops in a year or so, you can get a cab ride in a real Rio Grande loco. Ask the engineer, who will then clear you with the conductor. They will allow one extra person in the cab at a time, so if they are training a fireman or engineer, they won't take a rider, but generally it's not a problem getting on.
Good traveling!