Oooh, thanks, Preacher.  I had thought of seats, knee pads, and thigh straps, but I forgot about the feet.  
  Hmmm?  Would a couple strategically placed pieces of foam or maybe some bungee cord solve the road noise problem?  I hate to admit I haven't figured out yet how to ignore something like that.  Immature?  Crotchety? Anal? Or what?   :-?
  I'm a novice at this and haven't tried a double-blade yet, except as a Caribbean tourist in a plastic thing.  We had a thirty-some boat multi-club paddle on the South Platte here in Colo a few weeks ago, and from what I saw, all canoes had single blades and all kayaks had double.  Mere culture, or what?  I'll have to ask Mad_Mat when I see him; he's got tons of river experience.