When I plan a vacation I work on a daily itinerary. This includes leaving times in the mornings and arriving times at our daily destination. This includes rest stops and/or sightseeing stops. I give copies to friends and relatives in case of an emergency. This way they will know our approximate location.
Here is an example:
9:00 AM Leave New York City (Holiday Inn) for Philadelphia.
10:30 AM Rest stop at Molly Pitcher Rest Area on the New Jersey Turnpike.
10:30 AM Leave Rest Area.
1:00 PM Arrive at Holiday Inn, Walnut Street, Philadelphia. Include Phone number and complete address.
Also give description and license place of car you are driving.