I'm not sure i would agree that a rental is cheaper - it doesnt take much to exceed 400-500 bucks for a rental car in a week. My corp rate nets me a good deal but i still end up spending 250+ a week....even if you rented once a month i think buying a toad could be cheaper.
imo tow dollies only add to the complexity imo - you cant back up w/ a tow dolly....if you have to back up you've got to unload the car and then disconnect & PUSH the dolly outta the way.
tow dollys only add to the expense & storage isn't (usually) free.
not to mention of storage or security of the dolly while at the destination.
even if you have to buy base plates and a drive shaft disconnect you're money a head compared to the cost of a dolly.