I have a more precise solution to your request.
I sent a request to the developer of MyFlightBook to add a flight-distance calculation if possible, since I know he captures GPS location information during the flight. He got back to me right away to let me know that it's already there.
I, and others here, have recommended using the MyFlightBook app in the past to capture/create logbook entries and I recommend it here again for you to use to get your desired flight distance (and get a nifty electronic logbook that can be accessed with an app or on a website). With this app, all you need to do is start a new logbook entry, and tap on the Engine Start Time field and it will detect your takeoff(s) and landing(s) as well as your flight path/airports. (This is assuming you have Autodetect Takeoffs and Landings enabled in your profile in the app. BTW: also set your takeoff speed to 20 kts for a PPC.). To close out an entry, go back to the app and tap on the Engine Stop Time field.
When you use the website to look at a logbook entry that the app automatically created it shows a paperclip next to your N#. If you click on that it will show you your flight parameters (altitude, ground track, etc.), which is nice, and sometimes entertaining. This is where I was going to suggest the deveoper put the flight path distance. BUT it turns out that if you click on the Route (which is just to the right of the date of each entry in the list of logbook entries) instead of the paperclip icon it will take you to a page with a picture of your aircraft and a map showing your flight path. Just under that map it tells you your average speed and "path distance". That's what you were asking for.
If you find this app useful, which many here do, be sure to send a contribution to the developer. I know that's something I've said before, so to be clear to any readers of this post: I don't know him or get a kickback. (Although oddly enough, he lives in a town only about 15 miles from me.)