Would it make sense to send a letter/post-card/email to everyone, JW and non-JW, to raise overall awareness? A couple of years ago I had no idea what the WT/JW is. Also to inoculate the non-JW public and overall pressure to force the WT/JW to change. What if the WHOLE world was made aware of the practices of the WT.
I'm sure you could get a lot of support from millions of never-a-JW people. Like me here. Christians love causes to help/save/free people from tyranny and oppressions - especially from broke groups that use religion to control/manipulate people. If all found out how they break up families - the support could be overwhelming. I read these posts and I am shocked about what I have found and want to help great injustices. Bring world-wide attention to this.
I do like the fund raising campaign for the billboard. Everyone can see it. Perhaps contact a few of those mass mailers of junk mail we get. They may even be supportive and process everything at cost and use their mailing lists.
A bit of levity - but you could promote a sign up do-not-knock list that is regularly sent to the WT. A mass sign of how many people specifically reject their practices. Or realistically a petition signed (even digital online) by everyone to force change. Shine a light on the WT and expose them to everyone.