Personally? Provided you can approximate the relative distances and directions for players, possibly using weapon ranges, as well as what arc facings are and the like, you shouldn't really have to change all that much; of the spaceship combats I've run thus far, only one had anything else besides the enemy ship(s) on the map. I think starship combat might be the easiest thing to TotM in Starfinder, but I use a mix of map and ToTm normally anyhow when I run games.
|Joshua James Jordan|
I'm with you, Jason. I wish we could dump grid-based systems entirely but it has embedded itself deep within the 3.5/Pathfinder fan base.
If given enough creative time, I'm sure you could make a variant starship combat system.
If I were to do it, and I'm just riffing here, I'd turn that first piloting check that determines action order into a "positioning check". The ship's speed and maneuverability would grant bonuses. Whoever gets the highest roll can determine its relative position to the other ship(s).
A lot of the interesting pilot maneuvers would go out the window, so you'd have to think of a way to keep the pilot entertained still. Maybe the pilot makes an evasive maneuvers check on each attack. Basically, scrap the 10 base AC and have the pilot make a piloting check against each attack roll. Just something to think about.