As soon as you can, take out all the kit and get some protectakote down on the floor.
I delayed in putting it down in the back of my van, 12 months later had to pay out for protectakote and £120 for welding. If I had put the protectakote down in the first place I would not have had to fork out for welding.
With tap water being around the 100 mark, I would personally use the RO, what RO is it? 300GPD or 450?
If you can, get an IBC tank and have it filling whilst your out working.
I have a static system and its much more convenient, just fill the tank in the van just like filling up with fuel (if you get a decent transfer pump it takes less time to fill 250-400 litre tank than it does to fill your fuel tank)
Matt