hi terry
you have four options
van mount hose pumps and tank fitted in the van
trailer mount tank and pumps on trailer plus nhose reals
trolly system small 25ltr containers on trolly with pump box
back pack small container with pump carried on your back (very heavy)
each is personell preference and does depend on your size of van/car
also weather you need to walk along way from your van to reach the backs of your houses
we have van setup with hoses fixed in to van i find it easier as i dont think i could carry back pack all day i dont like to trolly as you are lifting 25kg in and out of the van alot of times a day.
But as i said it is personell prefernce and i am a woman so that does influence my decisions on set up,
my husband and son also work from van mount and they find it faster.
you will probably have a lot of differnt anserws later but hop this helped.
Regards Belinda