In Australia we have a jumbo Ford Transit van with capacity for 3 karts on racks, all fitted out with tool cabinets, storage cabinets for race wear, helmets etc. racks for engines (usually at least 3 spares), axles, plastics and complete rear assemblies, tyre and rim racks...and a kitchenette (fridge, sink, combi oven and cappuccino machine

)
We do all the work and repairs on our karts except for engine work which is done by one of two engine builders we use depending on engine type.
Its very convenient as the van is secure and ready to go at a moments notice, making a quick trip to the track very easy. Its also great for both transport to and support at regional races.
Here in Asia the logistics involved in racing leads us to consider either replicating what we have in Australia (extremely expensive) or seek team support for our activities - but with me trying to keep my nose out of kart setup so I don't annoy the mechanics too much!
From having helped me work on his karts since he was 8 years old, my son has a pretty good handle on how it all works and the cause/effect of a wide range of setup changes. Now he's learning how to communicate his wishes and thoughts with his team mechanics here. We have been very lucky in securing full team support for his program this year.
The team support allows us to solely concentrate on my sons driving technique rather than having to worry about engines, setup and spares as well, whilst still allowing him to be heavily involved in setup and kart dynamics.
Having said all that, its not all clear weather sailing as each team has it's own methods, processes and work practices, which are different to those that we have developed ourselves.