You might be interested in doing what I did for getting myself and my bike to Pittsburgh. Hertz has an office at the Allegheny County Airport at West Mifflin, PA. I rented a SUV from Hertz at the Crystal Gateway Marriott in Crystal City (Arlington). It was a bit cheaper renting at the Crystal Gateway Marriott than at National Airport which is less than a mile away. You can drop the SUV at the Allegheny County Airport which is about four miles from Homestead. The airport is also very close to the GAP trail. I don’t know the cost of the SUV now, but it was very reasonable the two times I rented it one way and paid no drop fee. BTW, Fort Myer is in Arlington. Have fun!