I usually plan to ride around 75 miles per day. I assume that I'll average about 10 mph, though I truth I can often make 12mph or even 15mph if I have a light load and little wind. I usually stop for 5-10 minutes every hour. On scenic tours, I'll stop more often to take photos. I try to spend at least an hour off the bike around lunch time.

Before leaving on a tour, I'll make sure that I'm capable of riding at least 60 miles/day with decent (~3000ft) elevation gain in 5-6 hours on a bike that includes all of my gear. If I can do that for two back-to-back days, and feel ready to ride again on the third day, I know I'll have a relatively easy time on tour.