When I finally got the Vermillion campaign up and going, I knew that I was going to have the PCs involved in both Hoth AND Endor. We began the game shortly after the destruction of the first Death Star, so I had several years of game-time to explore before we even got close. In retrospect, I suppose I could have started the game prior to the original movie and involved the players in that. It would have been a bit tricky, though. You could have characters on Tatooine while Vader is there searching for Luke. But you'd have to be careful not to cause /too/ much trouble or it might interfere with the movie story line. As far as the Battle of Yavin is concerned, I suppose you could have a few PC pilots, but if you go by strict 'canon', only 3 fighters survived the attack on the Death Star. I don't really go by canon, and I could see fudging this, but on Yavin, only the pilots really get any action. It might be possible to include everyone in a post-movie scene involving the evacuation of Yavin. But well.. that really doesn't take place 'on screen'.
When the Vermillion Campaign finally did reach the Empire Strike's Back timeline, I arranged for the team to be stationed on Hoth. Some were given jobs as pilots, others techs and others rode patrol like Han and Luke. During the sessions, I recall playing clips of the movies (on VHS) to take the place of 'cut aways'. It worked rather well. I know I got all psyched up, and I'm sure my players did, too. One of them (Steve, the other one) went so far as to claim the lines of one of the background Rebels. In the scene were Han decides he's going out to search for the missing Luke, Rick Oman hollers out. "I'll take sector
". It was a nice touch on his part. Of course, the characters knew they weren't going to be the one to find Luke, but that didn't prevent them from helping with the search. It was at this point that I threw a coordinated Wampa attack against them and Echo base (this was actually an omitted subplot in the movies). Several of them were wounded and had to convalesce in the same medical ward as Luke.
When the Empire finally arrived, the PCs were given the task of holding one of Echo Base's flanks. This allowed me freedom to throw a whole Imperial task force against them without stepping on the toes of the rest of the battle raging on the 'main front' (i.e. the one shown in the movie). There were tow cable attacks, speeders shot down, blaster-fights with snowtroopers, the whole nine yards. The PCs even got to see (from a distance) Darth Vader's personal assault shuttle land on top of Echo Base. Great fun. And then suddenly, the PCs realized that their evacuation zone was just overrun. It was then that several characters got the same idea simultaneously—"Hey. There's a shuttle on top of the base!" And so, rounding up their surviving ground troops, the PCs launched an attack on Darth Vader's shuttle. They took out the crew and flew off with it in the confusion. Yeah, it was close quarters for the whole team and the platoon of Rebel troopers under their command. But they'd escaped. They even dubbed the shuttle the "'lil Executor" after they found out who's ship it was. This, of course, led to a joke later on. In the original release of the movie. Vader was leaving Bespin after his duel with Luke. He rumbles menacingly and annoyedly to his subordinates. "Bring me my shuttle". My group (I can't remember exactly who said it) added to that line: "...If you can FIND it." I still giggle about that sometimes (and I'm slightly annoyed that in the re-release of the movie, they changed that line. Sigh).
After this, there was roughly another year of game time to handle before Return of the Jedi swung around. Since my first foray into mixing movies and adventures was so enjoyable, I did more planning for this one. The PCs found themselves reassigned to the main Rebel fleet as it prepared for its assault on the second Death Star. About half the group (Marko, Hugganut, Bob, Martell, Jared) was assigned as part of the commando team, while the other half (Arianne, Oman.. and I think Ruu'khan?) were given jobs in the fleet. It took some finagling to make everything work—and some prior agreement from the players to work within the confines of the movie. Again, as the adventure progressed, I used clips from the movie to serve as cutaways. And again, the players began to claim background characters in the movie as being 'them' (Martell was the black guy commando sitting next to Leia, Bob was the cloaked figure seen entering the strike team's shuttle, Jared was the commando who rifle-clubs the Imperial in the shield generator bunker, etc.) It was a truly memorable night and fun adventure, despite the fact that so much of it was 'scripted'. Oman was the top-turret gunner on the Falcon, riding along with Lando, Arianne was in control of a Gunship during the fleet battle—and the rest of the guys? Well, they had a hell of a tangle with the Imperials on the surface of Endor. Needless to say, everyone had a great time at the post-battle party in the Ewok village.
I recently (within the last couple years) ran a much smaller campaign for my friend Sharon and her husband Philip (with brand-new characters not related to the Vermillion campaign). It moved a lot faster than the Vermillion campaign (timeline wise) and I made a point of throwing them into the movies as well. Again, even years later, it was lots of fun for me. And as before, it really helps to tie the PCs directly into the movies. So, if you're running a 'classic' era campaign? Well, don't be afraid to really put your PCs in the movie.