This postcard was sent on 15 June 1938 to my great-grandparents Edgar and Alma Jones by my Gumpy, Keith D Jones. At the time, he was 17 years old and working as a lifeguard at Indiana Dunes State Park. The postcard was a great find, it shows the address for the Jones family at 133 West 20th Street, Apartment 12 in Indianapolis, after they had moved from Boone County (which I didn't have before finding the card at my parent's place back in April).
Indiana Dunes is about a 3 hour drive, depending on traffic, from Indianapolis. I don't know how long the trip would have been in 1938. Pictures and information about the park can be found at http://www.indianadunes.com/ and http://www.nps.gov/indu/planyourvisit/maps.htm.