Research and narrative design for Forced Farewell

After reading the deconstruction of detective stories, I had created a deck of playing cards with prompts and questions that were common to the genre. I'd shuffle and draw from these to generate ideas and eventually I ended up with the general outline of the mystery.

The hand I drew for this was: "Relationships", "Once you eliminate the impossible, whatever remains, however improbable, must be the truth.", and "The criminal is always someone from within a closed society".

Full spoilers ahead for Forced Farewell.
I had the outline of what would happen, but not when and where. It was an abduction story with the twist that the kid simply ran away because he hated his family but staged a crime to buy time. So far so good, but this is a story that could happen anywhere any time.

I chose the time in which the original Sherlock Holmes was set, but specifically 1889 because that's at the tail end of the decade where steam boats...picked up steam. That meant fares to America were lower and accessible and a renegade kid might get on board. Because the story required parents who had the means to be ransomed as well as a kid who would need to conceive of such an idea, I chose a landed family.

Now I had who and when, which drastically narrowed down the where. I simply researched where the cheapest fares for ships going to America were at that time. Then looked to the outskirts of those great ports to find where a noble family might live. I ended up around Romsey, in spitting distance of Southampton which had become the dominant port at the time.

With the major constraints now set, I looked at mansions where these lords lived and reasoned about how a kid might run away since they were usually in the middle of nowhere. What would he know, what would he pack, where would he go? And how could you figure it out and find him?

In Forced Farewell, a boy has been kidnapped and time is of the essence. In-world communication between the chief and the player isn't instant. Due to the urgency, they're sending telegraphs back and forth, instead of the regular letters, but time is still passing. I wanted to show the time pressure the characters are under with various ominous messages sent by the kidnappers. Since we had implemented the hints system where you'd get helpful messages from the chief every so often, I decided to use them to create the narrative and time pressure.

For example, soon after taking up the case this message is sent along the usual answer:
"Dear Mr. Holmes,
I'm sending you an urgent telegram. We have received a puzzling message in our mailbox today. Unfortunately there are neither sender's nor destination address on it. No postmark to be found. The same style of cutout newspapers has been used to communicate the message.
It simply reads: "The new address for the money is 221B Baker Street."
I may sound reckless in asking your continued support, even though this appears to be a clear message saying the thieves know of your involvement, and possibly a threat to your person. I will ask your local force for two constables to stand guard at your place. It might be a prank, but we must be careful.
Yours,
Constable Wellington"

This one is ambiguous, the next one carries a subtle clue, and the final one is basically directly revealing what happened, but the player (hopefully) gets the satisfaction of revealing it to everyone.

I had a great time researching and writing this story, and I'm looking forward to the next.