Movement
Characters do not have individual Movement rates, nor are 5 foot squares counted out. Rather, a character may use an Action to “Move,” allowing them to move to a nearby zone. This leads us to the concept of zones.
Zones
In those times that Movement needs to be tracked, like in combat, the battle area is abstracted into zones, always labeled from the observer’s point of view.
There are three types of Zones:
Close: Anything in the Close zone may be attacked in Melee and does not cost a Move action to get to. A Close zone can be large enough, however, that a character is considered close to an opponent, but not actually engaged in melee. Using miniatures is a great way to represent who is engaged in melee by putting them in base contact.
Near: A Near zone is one zone away from the observer’s zone (Close zone). It takes a Move action to move from a Close Zone to a Near zone. For the character making the movement, the Near zone moved to becomes their new Close zone and the formerly Close zone becomes the new Near zone.
Far: A Far zone is two Move actions away from a Close zone. As a character only gets at most two Actions in a round, moving to a Far zone leaves no actions left for attack.
Using Maps or 3D terrain with Zones
When using theater of the mind, a simple drawing of three concentric circles representing Close, Near, and Far (named so dependent of viewpoint of the person taking an action) will suffice. Simply place miniatures or tokens in the zone they are at and touch bases if they are in melee within a zone.
But what if you have sweet terrain that you don’t want to go to waste? The zone system can be used even with terrain. I use common gaming gems to mark zones.

The zones don’t have to have perfect borders. The GM and players just have to be clear with each other which zones miniatures are supposed to be in.

The advantage to using terrain–other than it’s visually pleasing nature– is that you can more easily keep track of tactical positions. For instance, a miniature can still use cover (hiding behind a pillar of the ruin) or elevation (Standing on top of the cliffs to the left and shooting down with a ranged weapon). I use the Advantage/Disadvantage system of +/- 2 dice to represent these tactical situations.
It could depend on just how big your battle map is, but I generally rule that a ranged weapon has a range of Far (two zones away from the shooter). If using terrain, I may rule a ranged shot is at Disadvantage if it is through a lot of foliage or even impossible if line of sight is blocked entirely. These are situations where the GM uses their fiat.