We are both in our early sixties, and hike about 1.5 to 2 miles per hour in most conditions. My wife goes slower in very steep (uphill or down, doesn't matter) and while we have done up to 14-15 miles in a day, we prefer to stay in the 8-10 mile range most days....and some days we only hike 4-5....or even take a rest day.

After all, we're supposed to be on vacation.
_________________________
Check our our website: http://www.backpackthesierra.com/

Or just read a good mystery novel set in the Sierra; https://www.amazon.com/Danger-Falling-Rocks-Paul-Wagner/dp/0984884963