Hello Larry Jay,
I read about your problem with sore knees. Last year I made a trip on my touring recumbent about 2240 miles and when I had made half of that trip I was affected by a severe pain in my knees. I decided to rest for a couple of days and change my technique of pedalling. After that I rode my bike again using a pedalcadence of over 90 rpm. Since then I have never had any problem with my knees.
erik f