Make whatever you're going to make on a hex grid, keep players position public for the most part, but notified at the end of turns. Set up a set of "when you roll" allowing you to add rolls to any posts where you think it may be needed. You'd be surprise how you can cover most of the basics. Then let PvP be decided on a "who acts first" system decided by the training score, and make the punishment for failing those rolls be a benefit to the other player. IE: "If you roll higher then X you hurt him, if you roll lower, he hurts you."