Some suggestions.
Don't flood them with phone calls. Ranchers leave early, come in late and seldom eat before dark. They are always behind with work. We have a depredation hunt going on right now and I get 6 to 12 calls a day. I realize it is a necessary evil, but keep in mind you are not the only one calling.
A small gift is fine if you want. A card in the mail for a Thank you and offer to help with some clean up, or working cattle in the spring would go a long ways.
They feed hay daily in the winter, and its a cold job. Maybe stop out with some hot coffee and donuts and offer to help feed a time or two.
Don't leave a deboned animal in plain sight or worse yet in the alfalfa field. That was the gift I got last night from a management elk hunter that did not even have permission to come on the ranch. Elk bones will play heck with a swather or conditioner if the hay grows up around it and it is not seen. I will be cleaning that mess up myself and his hunting on this ranch was a short story.
Hope this helps, good hunting.
Jeff