There is a group that still follows his teachings: International Bible Students Assn. (IBSA). They still sell his collected writings: Studies in the Scriptures - pretty cheap too. They also have it online. For the most part, it is deliriously dull reading - but it has some fun parts too. I actually bought an antique set. One interesting point you are likely to notice if you go there, is that they will claim that Russell was not the founder of the JWs - it was Rutherford. They refer to a time when Rutherford led a coup and booted faithful Russellites and replaced them with his own cronies.
I consider Russel a king of casuists. Take a careful read thru his logic on the Great Jubliee. He puts it out there like it is irrefuteable. Throughout the writings, look for references to it'it obviously follows', or 'it is clear to his followers'. Thats where you'll find the stuff he made up out of whole cloth. That is where he expects to pull some trash logic out of the trash logic bin, then tell you that he knows it to be true - and expect you to continue to read on, believing every word.
The most remarkable thing I've noticed as I read these books it their similarities to current publications. Most/all of the teachings have been dropped/rationalized away. But the overall tone is exactly the same as current pubs. Even the 'one question per paragraph' study mode is there. I was not surprised to find that the overall approach to the bible is the same: a jigsaw approach where the enlightened can interpret for the rest of us poor slobs. What was surprising were the exact terms still used today: things like 'in harmony with book this, verse that', 'true followers of Jehovah realize that', 'Esau class this', 'Ruth class that'.
I have done a fair amount of poking around and have not found much corroberation for the Masonic link. And I haven't read much that would imply any effect on the teachings.
His own writings should be about as hard an evidence as you could possibly need.
I can only guess that you are girding your loins for an arguement/discussion with a JW. One important point, as an organization, they have pretty much abandoned all the specific teachings and interpretations of Russell. You will get a big pile of 'new light' double-speak.
