I read this in grade school in the late 1970s/early 1980s. I believe the cover may have been in blue and white with an alien landscape. I recall the protagonists traveling in a moon-buggy r.v. of sorts. In a weird twist at the end, they discovered the energy bars they regularly ate had been suppressing their growth or their libidos or something like that. (Not in an adult way -- just preventing young boy/girl interest).
This is probably But We Are Not of Earth, also asked about '80s book about kids stranded on a planet and Story with student test to find a new world and bring back navigation data, teacher tried to persuade students to go native.
The details in this question are rather thin, but the key element (food bars that suppress romantic interest) is present, and the book definitely had a buggy for travelling around on the planet that the kids end up on. The 1984 publication date also fits.
The idea of food suppressing puberty makes me immediately think of Earthsearch which was a radio series - but it did have a novelisation according to wikipedia. I don't specifically remember a moon buggy but they certainly went to the moon amongst other places and travelled around in a few different modes of transport.