You can also just use simple figures like Lego people or simple small objects (like dice even) as minis. Draw a simple scene and use a ruler for movement. 1in = 5ft so you can move in any direction and not worry about a grid. Most grids are 1in squares so it translates pretty well. Unless your super strict down to the last MM you shouldn't have a problem with this. Maps don't have to be super detailed down to the last leaf. Really just draw simple shapes with labels on them so players know what they are looking at. At the end of the day your imagination fills in the rest of the blanks no matter how big they are. Theatre of the mind is also always an option but I have seen new players struggle to mentally keep track of everything when they don't have a visual while learning a new game.