Not familiar with NE WY hunting, but have hunted SE MT a bunch. We usually look for a MT BMA that takes reservations or a trespass fee hunt. Most public there is pounded pretty hard, but a public hunt is doable. Populations have been good since the last die off, smaller bucks all over the last couple seasons where we were, some better ones too. This winter has started out pretty hard there, so watch that and consider it in your plans.
WY has walk in areas, they are worth checking out I suspect. MT deer tags are expensive, 600+, which stings. There are plenty of opportunities all over in either state, not just those two corners.