Lucas: What Luke wants to do is to get on that barge and the only way he can do it is as a prisoner. He has to become a prisoner and Chewie has to become a prisoner; they have to unfreeze Han and they all have to be at the same execution, which is what his plan is. He figures once he kills the rancor, then they have to go to the pit. He knows that’s where the execution is going to be anyway. What they do with ordinary nuisances, or solicitors, is they drop them into the rancor pit. Luke knows or doesn’t know that is what would happen, what kind of trap they have laid for him. He’s assuming that when he is discovered and when he is subdued, which he will be, that he is bound to end up with Han and Chewie in the skiff over the Sarlacc pit.
The plan is, “I am going to knock everybody overboard into the pit and we’re going take off”—but it goes a little awry because Boba Fett screws everything up and suddenly they are in trouble and they get into the fight.”
Kasdan: You can assume that Luke’s plan is multilayered and the court of last resort is they are going to take him to the Sarlacc pit and they’ll all be in place. But when he comes in and says, “I want to bargain for Han,” he is hoping that will work.
Lucas: Yes.
I think the biggest problem I have with all this, is that if Luke intended for Chewie to get caught, it implies Leia was supposed to bring him to Jabba (disguised as the bounty hunter). But then Leia tried to free Han herself - which does not contribute to getting everyone on the sail barge, except insomuch as Han needed to be unthawed somehow. But if the goal was to get everyone on the sail barge, that means Luke also intended for Leia to be caught. Alternatively, we can interpret this as Leia going off-script and just trying to take the opportunity to free Han. (But then how was Chewie supposed to get out, and how was Han supposed to be unthawed in Luke’s original plan?)
Plus, it seems absurd to claim Luke also intended for Leia to be caught. That would be particularly reprehensible to me, because Luke would know of Jabba’s reputation and the way he is likely to treat captive women specifically.