did you think we all used tap water in our tanks?

trolley system will be fine.then if you want to go van mount at a later date just add a tank and 100m of microbore.
if you end up getting a lot of window cleaning work then lugging barrels about will become a pain and waste time when you could spend that time cleaning.ok as a starter system though.
check your tds from the tap.under 80 i would go for DI only.if its over then you ll have to buy an RO system to purify your water.
22ft clx is a good budget pole for starters.
regards
dazmond