Pressure washing commercial cleaning questions.

So I'm starting a new pressure washing business but do have some prior experience from other occupations. My main issue is that I had to move far away from any area I've ever worked and am not current on the prices in the area but I know it's high in demand despite being a more unwealthy city.

I feel I've underpriced myself, for the sake of exposure. Take for example, a gas station I've done wanted the concrete sidewalk, parking, gas pump stalls(concrete only), entrances, etc. It's a total of about 15,000 ft, hasn't been sealed in many years, hasn't been cleaned in 6 months minimum, and heavily stained.

Owner asked me to work past 12am when they close, and end long enough before open at 6am to allow water to dry and prevent tracking. Well problem is all 3 entrances slope inward at all 4 angles so anything your pushing out wants to come back in. And then on the street it angles back to the entrance for a good distance. Like half football field, so imagine a bowl inside a bowl thay tracks no matter what you wanna do unless you wanna spend 3 hours a night for a week+ to finish without some form of reclamation system. There's also no areas for natural filtration.

He said he's got a guy who does it but hasn't in a while and is just shopping around for best price and quality of work. Now I know that's a run-aound, band i played myself here but how would you guys handle pricing this and what would be the lowest price youd bid? Because even though it's not a wealthy town and he's complaining about our pricing, getting it done for the $600 he claims can't be true, or if it is there's a finer catch I'm not privy to in this industry.

Help a man out out who just wants honest work and honest pay with a family to take care of. I'm not ashamed to admit I'm a little desperate at the moment. Ive added a few pictures below to give a idea.