Mileage Calculator?

We are a mobile entertainment business.Can I add a calculator to the mileage form so that customers can see how far their event is from our home base?

You can add Driving Distance widget to your mileage form. This widget will return the approximate driving distance between two locations anywhere in the world. you can also set a default originating location. 

How to Add a Widget to your Form?

Hope this will help. Let us know if you need further assistance.