I got back into it when I was about 45, badly out of shape. I had no problem doing 50, 50, and from that point on 80-100 miles without anything in the way of training. Good news! Cycling is done while sitting down, sorta like TV. If you consider the average speed made good was 10mph, then 5 hours is nothing, what is one going to do with all the extra time? So I wouldn't underestimate how far you can go, if you are inclined to do so. Noramlly I would hit the road around 8 and have the first forty in the bag well before lunch. It always surprised me how fast it would get done. The rest of the day is a little slower, heat, shopping, fatigue... But it is easy to get a really big number by the time 9 rolls around.

I would recomend sorta a loaded touring approach if there are any nice places to camp, but keep the load extremely light. I did my earlier tours with about 35 pounds of gear including the weight of the panniers, but not the weight of water, or long term food. You always have the option of staying in the motel. I can't remember many motels, but camping can often be memorable.