as title says, how would it be to have tractor for farming, or jeep to pick up multiple colonists at same time, or war tank to position it in one spot so when pirates attack, each colonist can ride independent tank or 1 tank but multiple spots (like 1 colonist ride the tank to shoot the shells and the second use the machine gun that is put ontop of the tank)
I like the idea of vehicles, but yours sound a bit much at first. I was thinking about Star Wars swoop bikes, or just regular bikes, which would help colonists move around the map faster. You could also make carts of some kind to haul more items at once. It would really help out on large maps to have something to bridge the gap, and maybe make some other tasks like farming easier, though only marginally.
What about a mine cart system? It would be less op than fully fledge cars/bikes but still be useful.