[Gerald Ash]

In a camper van you have seat boxes or a larger van could have a fixed bed. Under such things you could easily store a tank and pumps.
 Motox vans are a good start but are on large size. Vans are not that much bigger than a car unless you are talking xlwb mercs or lts. You take a look at a Mondeo estate and a mwb transit, much the same length.
  I can`t judge on the trolley idea as I don`t think that a 125 litre trolley is that heavy, after all it`s a lot lighter than I am.