Firstly, ask your self is it necessary to have a First-Responder or is it practical?
Yes well then, a First Responder is exactly as it seems. It takes your priority calls, and initiates Patient Care, as soon as possible.
I guess setting up the car is relatively simple. The selection of the Vehicle needs to be made on practability, for example. Terrain, is it City based, Country. When you have selected a vehicle.... What nexed????
Fitting it out: what is the role of your First-Responder??? Is it to initiate treatment until an avaliable Bus is avaliable for transfer or will your responder unit transfer as well? Say it is only for Response jobs not patient transfer. Equipment.
What equipment is required? BLS or ALS.
In Australia, our First Responders and Advanced life support, (ALS) and are only ALS, with further training as we work solo. We respond from job to job until a bus is avaliable to take over, as our vehilces are quicker, obvious reasons. Our services has even enlisted the Aid of Motorcycles, fitted out with ALS equipment, to aid in quicker response times to isolated or hard to reach patients in large Malls if required.
I guess the thing you have to consider is the role, and your budget. You dont need the latest car, or equipment. you might be surprised you might have spare equipment to fit your vehicle out. just keep focused and on track and you'll get there mate.