Here's an EDITED idea.

Range = 1 light second per hex.
Detection: ships can loosely detect one another at interplanetary distances, but this is entirely insufficient for laser targeting, due to time lag. Missiles can be employed at ranges of 6 light seconds; lasers are -2 at 2 hexes, and -5 at 3 hexes. Laser fire is not possible at 3 light-seconds or more.
Time, approximately 1000 seconds per turn.
Since computers are assumed to be loaded, there will be no computer programming: instead, the difference between each side's computer power will serve as a positive/negative modifier to fire and ECM.

What about this:
Intruder movement as per MAYDAY.
followed by Native movement as per MAYDAY.
After each side moves, fire is resolved in three consecutive rounds, each consisting of:
Intruder laser fire
Native return fire
Intruder ordnance launch

Laser fire resolved as per BOOK 2 with the following adjustments:
Computers use the simplified form, with Computer number as a positive attack and negative defensive modifier.
laser fire to adjacent hexes=no modifiers,
1 hex intervening = -2,
2 hexes intervening =-5
-3 per sand (sand stacks)
Laser targeting not possible at greater ranges than 3 light seconds.
Missile movement "instananeous" within a range of 6 hexes, or 6 light seconds
Lasers destroy incoming missiles on 8+
ECM destroys incoming missiles on 7+, +/- difference between computers
Missile damage as per book 2, except that nuclear missiles do D6*d6 hits.

Whaddayathink? I gotta try this.