Personally, I don't think calling is near as effective as in person. A rancher doesn't know you from blue on the phone. In person, he will get a feel on what type of person he's letting on his land.
As a WI hunter that hunts WY every year, I've had the best luck meeting ranchers while hunting public land. Talking to them and not jumping to ask the "can I hunt your land" question. It might take a few years, stopping by the ranch to chat, some cheese, etc... Eventually you might be able to hunt BUT at least you've made a friend. Sometimes sacrificing a $300 tag to shoot a doe or a whitetail he wants thinned out.
Permission on a ranch when friendship is involved last much longer and is more productive than an informal, pay to hunt situation. I've never paid money to hunt on any of the ranches I hunt on. In fact, the relationships have grown to being invited to supper and even staying on the ranch.
Also, talk to the G&F warden. In my experience, they are a great resource and have always been real friendly with me.