Hard to pedal? Could you expound on that a little? Do you mean pedaling with the engine off and clutch disengaged? Or is that when you're trying to start the engine?
For wheel bearings, I recommend that you start by just greasing them. I believe the Shimano cb-E110 hub fits the same as the Cranbrook rear hub, so you can just swap the guts out and have a much higher quality rear coaster.
The best thing to do is to crawl through all the subforums and read the applicable sticky topics, read the FAQ, and watch an install video on YouTube. That can give you a real understanding of how it all works (without having to actually install it)