There's no rest for the captain of one of Marvel's biggest franchises.

Just months after the release of Guardians of the Galaxy Vol. 2, writer-director James Gunn is hard at work penning Guardians of the Galaxy Vol. 3, while also helping Marvel Studios head Kevin Feige plot out the future of the Marvel Cinematic Universe's cosmic properties.

"Those scripts are already in the works. Kevin and I talk about it all the time; we just had a meeting today. Discussing what is the next iteration of cosmic characters and where are the characters that we've already created going to go in the next batch of films," Gunn told Heat Vision on Thursday of mystery projects that would happen after Vol. 3.

Not much is known about Marvel's plans beyond 2019's untitled Avengers 4, but Feige has indicated that the film will be the culmination of the MCU to date, and things will look different afterward. (Only a Spider-Man: Homecoming sequel and Guardians Vol. 3 are officially greenlighted following Avengers 4.)

Vol. 3 will also be the end of this current lineup of Guardians, begging the question of whether the Ravagers led by Sylvester Stallone in Vol. 2 could pick up the Guardians mantle. There's a comic book precedent for that, as they were actually the original team of Guardians.

"I'm definitely interested in the direction that these characters are headed and their roles in the Marvel Universe," says Gunn.

Those Guardians have some wild origins that include time travel (they're from 1,000 years in the future), but Gunn says Marvel isn't planning on going that route.

"That is not something that we're dealing with. These are older characters and more criminal than our Guardians. So we're focusing on that," says Gunn.

Then there's the Vol. 2 end-credits scene that teased the classic comic book character Adam Warlock for the third film. The character is a key part of Marvel's cosmic mythology (you can read all about him here), but Gunn says he isn't afraid to craft a new path for him that could deviate from the comics.

"I always do what's best for the movie. A lot of times that means taking things from the source material, and other times it's changing things," says Gunn. "I've changed a lot already from the comics with the Guardians. Groot's personality in the first Guardians, which people loved, was nothing like his personality in the comics. He didn't have that puppy-dog innocence that we love about Groot. I don't restrain myself in any way when it comes to using stuff from the comics or not using it."

In regard to the role of Earth in the cosmic corner of the MCU, Gunn says the role would be limited.

"I think it's whatever works best for the story, but so far, Peter Quill has no desire to go back because he associates it with the pain of his mother's death."

Gunn also says he has selected all the songs for Vol. 3, and they're surprisingly different from the songs in the first two films. While he wouldn't disclose the amount of '80s and '90s songs included, his hesitation seems to suggest there are several entries from that era. (Perhaps we're reading into things a little too closely.)

"Vol. 1 was a playlist of Meredith Quill's songs, whereas Vol. 2 contained Yondu's songs," he says.

The conversation took place in support of Guardians of the Galaxy Vol. 2's home entertainment release (Aug. 8 on digital HD, Aug. 22 on other formats), so Gunn also had plenty to say about that film. Here are some of the highlights:

That Mary Poppins reference wasn't always planned.

In the film, Yondu (Michael Rooker) descends from the sky on an arrow, prompting Peter Quill (Chris Pratt) to note the similarities with Mary Poppins, the classic Julie Andrews character. But Gunn originally envisioned Yondu descending on the arrow to be a very heroic moment.

"When I was visualizing the scene, it didn't look quite as heroic as I intended it to be. So then I put the Poppins line in Peter Quill's mouth. And Yondu, of course, not knowing the name Mary or Poppins, might think he's sort of a Lee Marvin type, and he owns it," says Gunn.

The cast listened to music via hidden earpieces.

For both films, Gunn worked with composer Tyler Bates to write and record the score prior to filming. Gunn would play the music during the action sequences and other pivotal scenes, helping the cast get into it. As Pratt and Rooker fly off from Ego's (Kurt Russell) planet during the film's climax, they were both hearing the music via a hidden earpiece. Gunn credits the music, as well as the bond between the actors, for the potency of the third act, which saw Yondu sacrifice himself to save Peter's life.

"Chris, Rooker and I have a strong friendship, and the bond between Rooker and Chris really played out onscreen. We used our personal relationship in the scene, which made it a lot more sad," says Gunn.

Gunn avoids flashbacks.

One of the film's most powerful mental images comes when Nebula (Karen Gillan) describes how her adoptive father, Thanos, would replace parts of her body with machinery whenever she would fail to defeat her sister, Gamora (Zoe Saldana), in competition. As powerful as the image is, Gunn was never tempted to show that moment via flashback.

"I've used flashbacks at the beginning of both Guardians, but as a general rule, I try to avoid flashbacks," says Gunn.

When it comes to delivery, Gunn is very specific about how lines should be expressed.

The director coached David Hasselhoff on singing the "Guardians Inferno" song during the credits, and he can be seen finessing lines with the actors on the Blu-ray's expansive bonus features. Gunn cites Pratt as the actor who surprises him the most with interpreting his lines.

"I know Rooker's voice extraordinarily well; it's the same with Dave [Bautista]. Pratt is a crazy performer, so sometimes he goes off on a tangent, and it's like, 'Hey, Chris, come back to Earth.' Other times, he goes to someplace really genius."

David Hasselhoff wants Gunn to work on a Knight Rider reboot.

Hasselhoff made a memorable cameo in the film, with Ego morphing into the Baywatch star, a callback to the fact that Star-Lord always envisioned his dad looking like him. Hasselhoff, who also recorded a song for the movie, was on hand during Heat Vision's interview with Gunn and seemed keen on future collaborations — specifically one involving Knight Rider, his 1982-1986 NBC show about a crime fighter with a futuristic car.

"I've given some ideas to James for Knight Rider, and he responded in a big way. If it does go forward, I don't want it to be spoofed like Baywatch or 21 Jump Street. Those films lose what it's about, and you have to respect the fans," says Hasselhoff.

Guardians of the Galaxy Vol. 2 is available on digital HD on Aug. 8 and hits Blu-ray on Aug. 22.