I must be the only one on this forum who has used a trolley out of a car; used a reel from a car; used a van; used a backpack as an add on and used a trailer system.
Make that 2 of us.
For the OP. if its worked for 7 years why change it? If the cost of derv, insurance etc has gone up raise your prices to reflect it.
You will prob spend more to downsize and end up regretting it.
That said, the pure freedom trolly and barrels is not a bad way to go if you have to.