I have considered trailer and trolley and van mount options,trailer is a not viable at the moment because i only have on street parking so is not practical or secure,van mount much the same reason,because of filling tank,possible future option but want to build round a little first and i understand that backpack will always come in handy on domestics even with a van mount.I have not bothered with trolley(although was very tempted) because i think for now backpack is cheap starter and am planning to use some sort of trolley for water cans,I know there is an issue with constant filling,but for now,and for doing tops and/or difficult windows only i think it will be plenty until i have a bigger round.Only time will tell!!