Sean:
Live and learn! It's a freewheel, not a cassette. I had never really paid much attention to the difference, and the reason for the desirability of the cassette, especially when you're applying engine power to the axle through the gearset. Also, when I think about it, for a while I was having a problem with the engine refusing to go back to idle, causing chain snatch when shifting. I'm sure that didn't help. The drive side bearing being farther inside the hub would make a big difference.
Sadly, I just replaced my rear wheel assembly, but next time for sure it will be one with a cassette style hub.
Thanks a lot for your help. - I really appreciate it.