Thanks for the advice. My cadence is 80-85 rpm, that seems natural for me. The pedals are Shimano M-324. They have the platform on one side. I assume they are mtn (I have a recessed cleat) and believe they have up to 6 degrees of float in them, but when I am pedalling that doesn't seem like very much.
The LBS I am going to (and bought the bike from) is considered one of the best in the area. As far as their seeming reluctance to try Speedplays, they agreed it could be an option, but didn't seem gungho about it?? I thought it would be a foregone conclusion that we would try those next. And the owner mentioned all the "upkeep" they require. Quite frankly, any pedal that wouldn't cause me pain at this point would be well worth a little maintanance.