70 years old should have limit on miles per day.

I plan my trips for about 300 miles/day. By leaving about 8 AM, driving about 60 MPH, and with increasingly frequent rest stops for potty breaks, that gets me to my next FHU CG by about 3PM, avoiding the need for a reservation except for my final destination. I'm retired, so time doesn't matter a lot. If I'm ahead of schedule, I'll stay another night somewhere along the way. If behind, I'll go a little farther for a couple of days. Works for me.