The way it works with landowner tags is this:
1. The landowner can designate his tags as ranch only. If he does this the tag is only good on his ranch. This is usually done by the bigger ranches who outfit, as they can post their land and not allow hunting on it.
2. The landowner can also designate his tag as unit wide which allows you to hunt he entire unit, but he then also has to allow hunting on his property, by anyone licensed to hunt that unit.
Both types have advantages and disadvantages. My advice is if you go with the ranch only make sure you are not stuck hunting unproductive ground. We got screwed one year buying ranch only tags on a ranch that was the deeded access to surrounding ranches. Every morning all the other hunters would come through and blow the elk out. Don't be duped into paying more for unit wide tags also if the guy says you can hunt his ranch. He has to let you hunt it as well as every other person in that unit. I think NM G&F can give you a list of landowners and tags for the state. 52 is my favorite place to elk hunt, been hunting there for 20+ years.