kj, you don't stuff the recoil pad , stuff the buttstock since it's hollow. It only adds a bit of weight and quiets the stock down.

For hammer extension: http://www.bellmtcs.com/store/index.php?category_id=11 The medium rings will work fine with that extension, mounts and scope but you may need to file just a bit off the top back edge of the extension to keep it from contacting the scope. Depends upon how you position the scope for eye-relief.

A trigger job likely will not be "necessary" but might help a great deal in your performance with the rifle. Certainly nothing that can't wait until you evaluate the trigger for yourself. Bellm provides a free download with good instructions and you should get that download regardless. He also sells springs and hinge pins. Check that site out, lots of good info.

Swabbing the bore after each shot will definitely reduce fouling buildup, ease loading, and likely improve accuracy. Suggest an alcohol or Windex patch (lightly dampened) if using sabots but spit does a fair job. Use first the damper side, then the other and go in short up/down strokes as you work down the bore.

The extractor has only one small screw for retention but you need to take the forearm off to get to that screw. Just take it off and leave it off, Win209 primers come out very easily without it - at least on mine and several others.

I don't think that scope mount issue is quite as severe or widespread as you might think. None of the local Encore owners (only a small number) have encountered that problem.