The Rolling Stones was a fun re-read, especially after the recent re-read of The Cat Who Walks Through Walls (which was less fun).
I don't think this is technically classified as part of Heinlein's juvenalia, but it probably should as its pretty straightforward, light, and easily accessible.
The titular Stones are a family ala Lost In Space (thought significantly less lost, and if anything even more capable) adventuring around the solar system (mars, luna, the asteroids) essentially on a lark. Dad (a maybe sometimes professor? a scriptwriter who doesn't want to be one anymore? someone with a military and/or professional space man past?) figures dragging the family around the solar system is a good way to train and keep an eye on his genius, overachieving sons so they don't run off on escapades of their own. Those sons, Castor and Pollux, are some of the call-backs we get later in TCWTW, as is grandma Hazel. I find the Hazel here significantly more fun, interesting, and less off-putting than Hazel from the end of the World-As-Myth. Here she's at least believable as the matriarch of a family of geniuses, and isn't quite as broad ranging a polymath as she is later. This is also the origin, in some ways, of the World As Myth as the Galactic Overload is created here, by the family, as an ongoing antagonist in the scripts they continue to write to support themselves. We even get a weird hint at one point that perhaps the Overload is already real and interacting with this world.
Anyway, definitely worth the quick read, especially as it lacks some of the normal Heinlein trappings many people find objectionable. A straightforward, fun, swiss family robinson style adventure in space.