Land Valuation in Converse County WY

My family has some land in Converse County, WY and are looking to find out about how much the land is worth. It’s 640 acres (mineral and surface) with no development. We’re not looking for a formal appraisal at this point, but merely some idea of the value for estate planning purposes. Does anyone have any ideas who we could contact about this? We’d be willing to pay for the service, though like I said we’re not looking for a full blown appraisal at this point. Thank you!