"Rejoices" were July 1987. These were the first Knowledge Reviews led by Prem himself. I went to the first one of those, July 5-6, 1987, in Snowmass, CO, where we were divided into 4 or 5 smallish groups (maybe 100-125 people per room?). Prem worked his way around the 4 or 5 rooms showing us one technique at a time. Two days: first day we got through First and Second technique. He'd show us, and say, "Do this till I get back." No elbows-to-knees or baragans allowed. Then he'd go to the next several rooms of people, talking, demonstrating the technique, answering questions about it, then observing, then moving to the next room of premies. We did *each* technique for literally nearly 2 hrs because he spent so much time in each of the other groups' rooms before moving on. The second technique (previously called Music, until he renamed it "second technique" at Rejoice) is pretty painful to do for 2 hrs without supporting the arms -- I remember the pain between the shoulder blades vividly.
Second day we did third and fourth techniques (previously known as Word and Nectar) with similar length for each. I asked him a question on day 2, and got what I recall as a helpful answer. There were a lot of long-time premies upset at Rejoice because he rescinded his previous "commandment" to "constantly meditate..etc", saying that isn't possible, that Meditation is just for when sitting formally. Some premies left forever after Rejoice because he changed things up so much. (No more baragans! No more meditating while waiting for a bus! etc.)
I went to the next Rejoice a week or so later, which was in Palm Desert, CA, at a really fancy hotel. He didn't spend nearly as much time there doing each technique -- Snowmass was really the trial run and I think it was too long a day for him....
After that he went to White Plains NY for Rejoice 3, and somewhere in/near Miami FL for Rejoice 4, I think.
As for California programs in the late 70s or early 80s, can't help with Jim's question re that. I took a couple-year hiatus from programs sometime around Hans Jayanti FL in 79 or maybe after a strange program in the Stockyards' Rodeo building in Denver in maybe 1980. I remember a FL program in LA in ?1984 or '85, but can't recall for sure where it was, and Long Beach also in that general time period (with darshan).