All I can say is I would obviously have it in writing as well as all the details on access and usage. I would also have a long talk about how they will use the land, particularly if it impacts the animals or access. What is good hunting today could be lousy next year if they rotate crops, all of a sudden have 1,500 head where the elk were, cut in a new road, drop a single wide for ranch hands, move or drain water sources, or other stuff that routinely happens on a working ranch.
Sounds like it's not cheap, so just do your homework and paper it up well, overcommunicate and both parties are more likely to be happy about the arrangement.
You used to be able to easily search historical imagery on Google Earth, but I think they got rid of that function.
