I hope these haven't all been posted before; but I was just searching around on YouTube and found some really cool old videos from 1983 about the premiere of ROTJ.
The first is Siskel & Ebert's review of the film. The most interesting part is near the end when they reveal that Lucas planned to release 6 more films after ROTJ. I guess I can spoil it for you and just say that they both liked it:
In this next one, on an episode of Nightline, Siskel and Ebert get to defend the film against a critic who obviously has a stick up his butt:
"These films try to keep children stupid children forever."
Here's a local news story (not sure where from) talking about the anticipation for ROTJ from lines at the theater to toy sales. I think it also features the world's first documented scalper caught on tape.
Another local news story about toy sales, this one also repeats Lucas' promise for 6 more films, but the reporter is a little skeptical as to whether they will ever really materialize.
Finally, one of the coolest finds for me, a featurette on the making of ROTJ creatures hosted by.... Mr. Spock! I like this one mainly because it has a lot of cool close-ups of the Skiff Guards, especially Kithaba.