My one tip might be to learn to ride by spinning an easier gear faster. If you get a cyclo computer get one with cadence. Even after 10+ years of riding the two things I ride by are cadence and heart rate. Speed is just not that useful to me, unless I'm really trying to do a performance based ride.

If you can train yourself to spin a cadence of 85-95 you'll save your legs and knees and can go further more easily. It might test your cardio to begin with but just ride using earing where you can pedal 85-95 and still be able to talk without gasping for breath.

And riding into a headwind sux.....just use easier gearing and go slower.........