Some Software you may find helpful
Joinr (Android & iPhone) We have been told that several Porsche Clubs have used this app to create rally's and driving events and it has worked flawlessly by participants. We do not yet have a report from an Ambassador.
My Route (Android & iPhone) Designed for delivery services that need to plan their route. It's is still in development and has some bugs. Once you have you map correct, it works quite well and prompts you turn by turn. You can also print out a copy of the route plan. There is a one time fee or $39 to create your route. The developers are accessible. ~ Bernie, July 2020
Rallista (iPhone only) - Requires you to pay $2.99/month and it is limited to only about 10 cars that can use the app. The easiest way to create the route is by driving the route and recording it. The map data is sourced from a trucking company and there are errors. (e.g. one way streets that aren't). The developers are accessible and the product is undergoing lots of updates and bug fixes.- ~ Bernie, July 2020
Google Maps