hello lee, no wisdom really necessary. It is very easy to do. I have been using mine as a van mount for a while.
The hozelock push fit connectors aren't much good for joining the tank to the trolley as they leak.
I use one of those hozelock connectors that connects 2 pieces of pipe together. These are screw fit, so easily detatched and they don't leak.
A metal reel is better than the palstic reel i use as i need to have a hozelock push fit to connect. Leaks. You will be able to buy a swivel connect so you could have a leak free joint.
Oh and the best advice i can give is get a 12v submersible pump and just refill 1 barrel. Much quicker than the trolley can produce a barrel full.
Put this in the tank and drill a hole in the lid and have a length of 1 1/4" hoze with an on/off valve on the end.
This is a very efficient way of working with a trolley and to have the best of both worlds.