Maybe Abstract movement for scenes can be simple as Range Distances... Think of each distance as a Increment or Zone (I think this is how its done in Spirit of the Century, but I can't remember)
Adjacent: 0 distance
Point Blank: 1 Distance apart
Short: 2 Distances apart
Medium: 3 Distances apart
Long: 4 Distances apart
Far: 6 Distances apart
Extreme: 8 Distances apart
Maybe creatures of different sizes can have a simple move like...
Short/Medium size = 1 move distance
Large/Huge = 2 move distances
Gargantuan = 3 move distances
Collossal = 4 move distances
I developed an abstract movement for my game as follows:
Adjacent: right next to each other, melee combat range
Close: within about 15 feet of each other, reach/polearm/point blank range
Short: within about 30 feet of each other, charge range or for fighting with ranged weapons at no penalty
Medium: within about 120 feet of each other, double-move range or for fighting with ranged weapons at a one-step penalty
Long: within about 240 feet of each other, two rounds of double-move or one running round away, or for fighting with ranged weapons at a two-step penalty
Extreme: over 240 feet away or so, three or more rounds of movement away, or for fighting with ranged weapons at a three-step penalty
Well, I love this idea, but if you combine the two directly (i.e. compare the number of feet away with the move distances) and consider the average (D&D) movement rate for a medium two-legged creature (non-dwarf) is 30 feet, it doesn't quite work out. I played around with it a little, and I think that it needs one more range (speaking as one who has never played without miniatures for combat, so I understand I may be wrong in practice)
Adjacent: 0 move distance. Right next to each other, melee combat range
Close: 1/2 move distance. Within about 15 feet of each other, reach/polearm/point blank range
Short: 1 move distance. Within about 30 feet of each other, one movement away or charge range or for fighting with ranged weapons at no penalty
Medium: 2 move distances. Within about 60 feet of each other, double-move or charge range or for fighting with ranged weapons at a no penalty
Long: 4 move distances. Within about 120 feet of each other, 2 rounds of double-move or one running round away, or for fighting with ranged weapons at a one-step penalty
Very Long: 6 move distances. Within about 240 feet of each other, 3-4 rounds of double-move or two running rounds away, or for fighting with ranged weapons at a two-step penalty
Extreme: 8 move distances. Over 240 feet away or so, 5 or more rounds of movement or three or more rounds of running away, or for fighting with ranged weapons at a three-step penalty
Reach would have to be taken into consideration, of course. I'm not sure how to take into account the speeds of different creatures. You wouldn't want 'halfs' in there, and a number of D20 things affect speed in 5-10'/round increments (size, armor, dwarves, number of legs for monsters, etc). You could, however, just eliminate that element of complexity from your game. A fast medium creature like a wolf could have a movement of 2.
Instead of 1 movement =30 you could make 1 movement =25 (then it would go 5, 15 (or 10), 25, 50, 100, 200, >200) so the numbers are more even.