I can tell you from experience that a five hour straight drive is NOT recommended medically. Regardless of your age, blood clots resulting from immobility on long drives, plane trips, etc. is a REAL possibility. Happened to me 2 years ago on a long trip because I found it difficult to stop and take a short break due to road conditions, night, etc. I now take a break to get gas, stretch, get a coffee, or just pull off the road to a side road every 1-1.5 hours. Good planning of a trip helps with this and usually results in minimal extra time.