Looks good,if i wasn`t already set up i`d buy it.
A 4040 with filters, connectors,membranes etc won`t leave you much change out of £600 to set up yourself.
Ideally i would recommend you de-mount the RO and mount it on a board,use it to fill a static and then pump to the van.That way you get to keep it inside when you like in case of minus temperatures.