This falls under the principle of include three clues for everything. It also is well suited to the approach of using environment-based storytelling.
Use Environment-Based Storytelling
Introduce the puzzle setting first and let the players be confused over the weird specificity. I like the petrified inhabitants part; maybe have the husband-farmer and wife-farmer wearing crowns, placed upon them by whatever mischevious fiend set up this puzzle. The players probably won't understand what's going on, but you can include enough detail that they will find it weird. Including a visible goal will help: a chest in the corner that's sealed with mystical force or an unopenable cellar door with the symbol of an inverted crown on it.
Once the players' curiosity is piqued, they will probably resume exploring. Here is where you can include your clues: a mocking poem in the children's room about farmers becoming kings and queens and a horse becoming a knight, a chess set out on the table in the parents' room with only three or four pieces on it, and so on.
Provide Many Clues
Even if you include what feels like too many clues, your players won't notice. They'll find just enough clues to figure out the solution, and then they'll stop looking. Even if you include an extra clue, they'll feel clever and excited that they already know how to interpret that. In the worst case, if they figure it out immediately, just leave out any remaining clues as if you expected them to get it quickly.
As far as worrying about being too obvious: your players have a lot on their plates. They're visualizing a world you're describing, balancing resources, and keeping in mind their larger goals in the world. Picking up on even obvious clues is enough of a challenge. Recognizing that the "king" and "bishop" in a message refer to chess pieces seems obvious in planning, but it's an impressive leap for a player who's already juggling a bunch of other knowledge.
As long as you don't have them find a note that says "THIS IS A CHESS PUZZLE AND HERE IS THE SOLUTION," you're probably not being too obvious.
As for being too esoteric: have a backup clue that stops just short of the obvious note above, and if it seems like they're moving on without solving the puzzle, place it in the next place they look.