If you are hunting with someone who already is familiar with the ranch they will likely have an excellent idea of where the elk are but learning general elk tendencies is a good idea. Showing up in shape and able to hit targets the size of a gallon milk bottle at 300 yards from a good field rest is a very good idea.
Well broken in waterproof leather boots with enough insulation and clothing layers to add for sitting and take off for hiking. Orange hats are required in Co as well as 100 square inches above the waist. A baseball cap stocking cap and vest is about all you normally need. It probably gets colder in Iowa but climbing hills at elevation will require only light layers unless you want to be soaked with sweat. Then sitting on a windy knoll you will want something warm. I need a good backpack to haul out meat - that may not be required or could be essential depending on access and terrain.
Other than those basic things it depends on your area. Ask as many questions as you can and take a good look on google earth.
