Several methods, don't know of an alarm.
I had less busy airspace unless getting within 40 miles of ORD. Using the home airport in a flight plan, keep it active so it always tells the distance.
Doing an altitude speed run for various data reasons can use a lot of space in the RV!!
The WPT circle method works off the IFR charts and you can make your own WPT's in the Garmin products.