We just finished our first loaded tour along the Santa Ana River Trail in Southern California. The trip was 30 miles. The way out took us 3.5 hours with about a half hour worth of stopping -- so 10mph. The trip back took 4 hours with about 1.25 hours of stopping -- so quicker paced but we soaked in more of the scenery. We all agreed that the pace was good and, though tired after it all, we had enough steam and endorphines to go out to dinner and walk along the beach

I'd say to keep the spedometer if you're intrigued by distances like I am, but dump it if you find yourself racing the clock. 10 mph is plenty!