if you have enough containers in your van to start with you wont need to keep filling them up, and you dont need a van mount or 650ltrs of water for a days work either.
Anyway i have a 25 ltr purefreedom trolley really good quality built to last , i carry 10 containers ,250ltrs of water which does me a good days work on domestic , I have a attached a 10 mtr retractable air hose reel to my trolley which can be bought of amazon for £35.00 but you need a one with a bracket like this next symbol [ not great i know this will allow you to attach to trolley with large cable ties and its pivioted ,
You will need ez-snap fiitings from gardiners male and female ends ,
I also have my pole fitted with 10 mtrs of pole hose , clx 25ft from gardiners should do as good light pole and will allow to reach above connys etc , i would but your ro unit from purfreedom and containers if you decide to buy trolley from them ,, Had my trolley over 3yrs now and still going strong really solid build ,
i manage really well with trolley and personally can never see myself wanting a van mount and you dont want to be spoiling your classic van mate