I'm running an ongoing game with characters starting from the bottom in the OT era, but I've got the itch to design a one-shot for higher-level characters to give my players the ability to cut loose and have fun being awesome at some point when we hit a break in the campaign. I'm planning on setting it in the years leading up to The Force Awakens because that's a nice open playground at the moment, and the premise I'm working with is "prison break" because that's a good self-contained plot for a session or two.

Thus far I've tentatively decided on the following:

1. The player characters are scum, villains, and other dangerous types who have been (Wrongly?) incarcerated in the infamous Star's End prison at the edge of the galaxy. Because psychopathic monster PCs don't really make for fun roleplaying, I'm going to suggest the players brainstorm who their character pissed off or what crime they were framed for to end up in prison.

2. While being transferred to Kessel as part of an exchange, their ship is attacked and hijacked by members of the fledgling Resistance against the First Order (Timeline is ten years prior to the film). They want to rescue several of their people who are being held in Star's End, and they want the player characters to help them do it since they're familiar with the prison and are dangerously capable types. As incentive to take the deal instead of just running for freedom at first opportunity, they're willing to pay a lot.

3. There will be a twist at the end, which I'm leaning towards

There are a couple of problems with this: I have no idea how much extra XP to give them, nor do I have any experience in running high-level games that aren't utter cakewalks or absolute death sentences.

give them 500 XP after char gen and you should be good.

There is quite a few threads here about the potential pitfalls of high level gaming with this system. I highly suggest doing a search and reading up on them. With that, the general consensus is that most if not all of said pitfalls can be avoided if the whole group can come to agreement on certain expectations.

Player: "I will not make a one trick monkey of absolutely crushing proportions that will completely crap out on anything besides my on trick."

GM: "I will having meaningful challenges that will require a full spectrum of capabilities so that everyone, no matter how there characters are build will be able to participate and feel like they are contributing."