Unless you just have a ton of hex paper, I would ditch the hex paper and switch to 1” squares. Why? Well, I was just looking at your road there. Traveling west to east in a straight line along the road requires an odd up, down, up down, as the hexes don’t align quite like squares on a game board. So, for young minds, I would have the visual element be a bit more intuitive with a clear grid and clear x and y axes. So, if you move up, for example, you can clearly count y squares up.
Second, define your scale. For example: A “near” move is “four squares.” A “far” move is double that, or “eight squares.” Close is touching. Then, just reinforce the terminology every time you play. “You can make a near move, which is four squares.” “How many squares can I go, daddy?” “You can move four squares (a near move) and still take an action.” Eventually, as they grow older, they will associate the concrete number of squares with the abstract term.
But truthfully, I wouldn’t worry about it too much. At that age, it’s just great to have them moving, RP’ing, taking actions, and participating in making a story. Fun really should be the name of the game versus too much of an emphasis on abstract terms like close, near, and far.