Shop the exits. Enter a road trip and DETOUR finds every local-marketplace region within a tolerable detour of your route, ranked by what each stop costs you in minutes — with the searches pre-built so you’re not typing into a phone at 70 mph.
This is DETOUR's reference route: … to …, 4,353 GPS
points, about … of driving. The candidate towns were found by the tool's own
detect_corridor() — project the route to an equal-area CRS, densify it, and take the
perpendicular distance from every Craigslist market to the line. That geometry ran in Python, because
reimplementing an Albers projection in JavaScript would be exactly the kind of lookalike this site keeps
promising it isn't building.
What runs here is the part you actually turn: cheapest
and spread from corridor/detour.py, ported honestly — including the bit where
spread trims 30 minutes off the start and 45 off the end, divides what's left into equal
segments, and makes one rescue pass at 50% wider before giving up. Segments that are genuinely empty
stay empty; the tool degrades honestly rather than padding the list.
This is the actual output of the engine on the reference route — 11 marketplace regions found inside a 25-mile corridor over a 7.2-hour drive. Flip between the two selection strategies and watch the stops redistribute. That difference is the whole product.
What you’re watching: in Cheapest mode the greedy pick clusters Hudson Valley, Hartford and the early stops into the first few hours — you’d shop one region and burn the budget before New Hampshire. Spread cuts the drive into equal time segments and takes the best stop in each, so the finds are distributed — and it honestly leaves segment 1 empty rather than forcing a stop that isn’t there.
Driving Beacon → coastal Maine means six and a half hours through Connecticut, Massachusetts and New Hampshire — each with Craigslist regions and old New England housestock that turns over inventory I can’t get at home. I wanted to know, before leaving: which exits are worth taking, what each costs me in time, and to have the searches already built so I’m not typing at 70 mph.
The hard rule I set, and the whole reason the engineering is interesting: DETOUR scrapes nothing. Not Craigslist, not Facebook Marketplace, not OfferUp — ever, in any milestone. The value isn’t re-hosting listings; it’s the routing math that tells you where to stop.
The corridor detection has a golden-file test on this exact route: it asserts Hartford, Worcester, Boston and the NH/Maine regions appear in the right order, that Maine resolves to subareas including Portland, that nothing exceeds the buffer, and that spread and cheapest produce different sets. The geo core is finished and green.
DETOUR is milestones 1–2 of a documented six-milestone spec: the geo core and the probe builders, shipped and tested. It was carved out of a larger platform (QUARRY) specifically so it could ship in a weekend and stand alone.
This is the one project where the “unfinished” parts are a numbered plan, not a stall — scope discipline with a paper trail.