A Chest of Crowns
Amass a hundred thousand Bits.

Rule: your purse must hold 100,000 Bits or more at once, checked at the end of every day. Bits out on loan or sitting in shop tills do not count. This is a long one: about fourteen years of game time on this route.

Route

Start a Hush runner with the Outlaw trait (8 on the New Game screen): Hush Trade runs pay 450 Bits instead of 300, offers come more often, and only one in twenty is a sting. This run also took Discreet (2), which only protects bribes.
Set Settings → Auto-pause to Monthly and let Auto (Space) run the days: it stops for every Hush offer, crisis and monthly check-in.
Take every Hush offer (Y). Smuggling is the engine of this route; the run completed about ninety of them.
When Watch suspicion reaches 30 at a check-in, confess (Shift+C), which costs standing but clears the slate before an arrest. If a run is a sting, post bail (X) as soon as you can afford it. \ Skip ahead does not open in a cell; trade days with Enter and weeks with Shift+Enter.
Keep two shops for steady income: buy the first in Confluence Spit (B), retool it to the wanted good (T), press , until the plan reads 50% of market, then hire a hand (H) and promote them (A). Buy a second shop once the purse covers a third over its price.
Do not lend and do not spend on offices: the achievement counts only the purse.

This run passed 100,000 Bits on day 5266 (Year 14, Harvest 42), aged 31, after two arrests, six confessions and one catastrophe, a Trade Blockade, answered by selling dear (E). Its twelve test worlds all reached the goal, the middle one by day 8176, so plan for a long life. Your world will not match this one day for day: prices, figures' moods and catastrophes come from the world you are playing. The decisions are the same.

Full run

Thirteen minutes. It plays at 1.5× from the first day to the final achievements screen, as the label in the corner says; the menus run at normal speed. The run was played by a scripted player through the game's normal controls, not by a person, and screen-recorded on a fresh profile. The game's own music and effects, no commentary.

Play screen with 100,154 Bits in the purse in Year 14 — Year 14, Harvest 42: 100,154 Bits in the purse, top left. The lantern among the Powers is the Hush Trade, at +100.