This applies to both your short gas coach with toad and our longer DP with toad:
Start by using
http://then.gasbuddy.com/Put in your location. Click on map and scroll along your route to determine the cheapest fuel ON YOUR ROUTE.
Then, take the address from gasbuddy and put it in:
https://www.google.com/mapsLook at both satellite and street view to see if there is any problem with entrance/exit.
Enjoy the savings. Worked for many years. BTW, using this, last fill up with diesel was $1.63. Nearby locations were over $2.00.