Fleet Washing opportunities

I have had several opportunities for some random fleet washing jobs via word of mouth. I do not feel I have the set up/tools for this yet. With winter time being slow for residential, and the central Texas region not the arctic, I am looking into this to keep a little cash flow coming in.
5gpm hot, 3500psi. mobile, (do not have own location to wash them)
Are there special tools, brushes needed?
chemicals/mixes that work best?
Pricing for individual vs contract for business.
Any help is appreciated.

How many pieces, kind of vehicle, how often is the wash, water onsite etc?

Greenwater Pressure Washing

Tractor/Trailer. So far opportunities have been limited to random calls regarding truckers passing through Austin area who need them washed. I do not have an onsite location, nor do I have capability to carry enough water to them at this time.

How much water can you carry at the moment?

I have a 35g tank with a float. Do mostly residential.