The easiest thing to do is sketch with a pen on gridless paper to create the map, and then use a pencil for people. Run it fast and loose.
If you want actual rules, consider this:
Move, the ability score.
In addition to Str, Dex, Con, Int, Wis, and Cha, you have Mov. You don't roll for it; you just have the appropriate Move score based on your race, encumbrance, class abilities, etc. You have an ability score modifier too, just like the other ability scores. So a Move of 30 (your typical human) has a +10 bonus to Move checks.
There are ranges in combat that are very simplified.
Melee - a roughly 30-ft. radius area. This is basically where people will engage in melee. There can be multiple melee areas in a combat. Moving from one to another is a move action.
Medium - a roughly 150-ft. radius area. This is the maximum range for thrown missiles, and normal range for projectiles. A Medium area can potentially contain several melee areas. Moving from Medium to Melee or Melee to Medium requires a Move check. If you beat DC 40, you can change range as a move action. Otherwise it takes a full round.
Long - a roughly 800-ft. radius area. This is the maximum range for projectile missile weapons. Moving between Medium and Long range requires four move actions. For each move action, you may attempt a Move check (DC 40), and if you succeed you actually move two move actions' worth.
There are some new actions in combat.
Engage: Move action. Make a Move check (DC 0 + target's size modifier + target's Move modifier). If you succeed, you become engaged to the target. Effectively you are keeping close enough to that foe that you threaten him, and can take attacks of opportunity against him. Having a creature engaged to you does not necessarily mean you are engaged to that creature.
If you fail, you may choose to still attack the foe, but you do not become engaged. Or you may choose to engage the foe, but the foe gains an attack of opportunity against you.
You must be engaged to a foe at the beginning of your action to make a full attack.
Disengage: Move action. You are no longer engaged to one foe that was engaged to you.
Withdraw: Make an opposed Move check against all foes that are engaged with you. Each foe whose Move check you beat, you disengage from. You may also choose to disengage from other foes, but each of those foes can make an attack of opportunity against you.
Threaten: Full-round action. Sort of the reverse of 'full defense,' you spend your round being opportunistic, trying to keep people from moving around. If you take the Threaten action, whenever a creature makes a Move check, if he fails or succeeds by less than 5, you can take an attack of opportunity.
It might actually be more complicated, but it requires no maps. Some skills would also need to be changed, and feats like Mobility and Spring Attack.