20-25 mile rides are doable on upright bikes with suspension forks, but you'll expend the same amount of energy and go slower in comparison to something like a road bike that places the rider in a more aerodynamic position and is stiffer. You will also have less hand positions (some solve this by using bar ends, or switching to butterfly bars) and suspension forks often do not take fenders quite as 'gracefully', but it's still doable if you are fine with that fact that you will be going a bit slower for the same amount of effort.