I do a row of semi detached houses (9 in total) I park the van in the middle of the street. Pull the hose from the back to the back of the first house and then work my way up the street one by one. I have 100 mts of hose and not all of it gets puled off. I place signs at each end of the path and move one with me as I work towards the other. Its a really good earner and If I had to do that with a trolley I would go bonkers (and yes I have done it). My trolley now only gets used on two jobs and Im thinking of sacking them as its a hassle once your happy with how to use the van mount efficiently 
trolleys can be a pain. But if set up right you can fly rounds jobs that use less than the 25 litres it carries.
You need 3 things to make trolley work fast.
A water tank in your vehicle and 1 barrel for the trolley.
A decent 12volt submersible pump that will fill up the barrel in the time it takes to write the chit. (Or roll a ciggie if they are home)
And hose that will allow you to park the trolley in 1 or 2 places and work from there.
I used longer pole hose as it was very light, didn't knock over or muscle plants out the way. The drawback with this hose is that it is fragile and prone to spring leaks where it splits. Insulation tape sorts that 1 out though.
Other people use different hose. Horses for courses.
! good thing is learning how to do a good job using very small amounts of water. This would be the same with backpacks.
The trick is to be able to complete 1 job or 2 neighbouring semis without refilling. Refiling a barrel is a pain if doing it before completion of a job. But is very little hassle while loading the van.
Saying this, i use a van mount now when i can. 400 litre water tank, flojet pump and microbore. I get through more water now as i use a much higher flowrate. But i find i am much quicker with a higher flow.
I've used a van mount more since last october, cos after 12 months of pain and struggling to walk (though i could work ok) i was diagnosed by a masseur that i had a raised hip. Something the nhs never spotted.
She described exactly how i lifted so i stopped using the trolley for all work. After 2 weeks the pain had gone.
This isn't a dig at trolleys, more my lifting technique. Or lack of it. I never followed a safe procedure. I just used to throw it in as quick as i could by flicking it up with my leg.
For me it would be a trolley everytime if i could afford the extras. It runs as a van mount but is detatchable. There is no other product (apart from trolleys) on the market that i know of, which can do both. And it can be very quick if doing the the things mentioned above.