Just curious, but is your seat high enough? Obviously I don't have enough information to tell you otherwise, but it just looks low to me even for someone with short legs.
Top tip, when sat on your saddle place the heel of your foot on the pedal (even though you should actually pedal with the ball of your foot).
Your leg should be straight when the pedal is in the 6 o'clock position.
Once you have adjusted your saddle to the correct height, your proper pedal stroke (using the ball of your foot) will leave a very slight bend in your knee at the bottom of the stroke.
This gives you the most efficient pedal stroke in terms of butt and leg muscles used, and minimises the stress on your knees.
I envy you. I had some things happen, both positive and negative, resulting in me not getting out nearly as much as I'd love to (and need to).
Trying out some new gear, taking some pictures, recording bird audio, baking bread in a fire, simply riding or whatever else justifies being out there... every little trip just adds so much.
Kudos on the 20 mile trip, keep going, you'll be back in shape in no time. Hope you like your new tent as well.
It looks like a great tent! GoLite used to have one like that back when they were a new company and I really wanted one, but couldn't afford it. Is that a trekking pole in the center, or does it have a dedicated pole? Is there an optional floor and bug liner?