Keeping from making a $8656.11 mistake with fuel

When I like propane for clean exhaust, the conversion systems usually drops the economy quite drastically and most important- fuel availability makes huge difference.
When camping around a lake I can easy buy gasoline at local hardware store pump, or marina - propane refuelling often require 25 miles drive to the city.
It is also way easier to bring 20 gallons of gasoline than 20 gallons of propane.