You may only access public land both BLM and State via a public road such as state highway, official county road or in a lot of cases a BLM road if the BLM road starts on a state, county or federal road you may use it to cross private land.....You are considered trespassing if you cross private to reach BLM land on a private road.....Therefor there is a lot of BLM and State land in WY that is "landlocked" to its rightful owners which include you....A lot of ranchers used to allow access to these lands for free or a small trespass fee, but some large and unscrupulous outfitters have bought the rights from these ranchers so these ranchers no longer have the right to grant an average person the right to reach these parcels.....
The BLM roads are marked on the BLM maps, but in a lot of cases the roads fork so many times that it is hard to verify which one is the actual BLM road on the map.....Also there seems to be a lot of illegal posting of BLM lands and BLM roads (Also State land)....Report these when ever you find them....Make sure and don't guess....Also be aware that there are some out there that will tell you you are trespassing when in reality you may not be...They might even ask for cash in lieu of calling the warden....That is why good maps and a GPS are imperitive to hunting the BLM & State lands in Wyoming, especially when they are interspersed with private land...
Also keep in mind that corner to corner crossings are not allowed in WY and it is considered trespassing, even though there is no actual law against it....A GPS is not accurate enough to precisely locate the corner anyway....
Good luck in your research,
Randy