Rather than a golf cart or gator/rhino, consider a zero turn mower
without the blade deck.

Onboard starter for the large airplanes would be very helpful.
Switch to electric power for the small planes.

On the trailer that carries the cart or mower, add a fold down
or slide out "table." Also add an electric "lift gate" appropriate
to the size of your rc equipment. If your needs are small
you could make it hand powered. Mostly it will raise things
up from the ground to where you can handle them and
then put them back down on the ground again.

If taxiing in the pits is forbidden, as is normal, make a
stick with a large loop of string at the end. Put the loop
around the prop hub and pull the airplane around. Don't
worry about hurting the engine. It pulls the plane around
all the time.

Jenny