The Saturday-evening reservation at Le Coquillage is not just the social anchor — it is the geographic one. Hugo Roellinger’s kitchen sits on the ground floor of Château Richeux on the D155 between Cancale and Mont-Saint-Michel; service runs to about 23h30 and the closest streetlight is several hundred metres away [1]. That one fact forks the rest of the weekend into a single binary choice — sleep where you eat, or budget for a return taxi.
The on-site stack is one phone call. Château Richeux, La Ferme du Vent (off-grid kleds 400–500 m through the gardens) and Les Rimains (cliffside in Cancale, 5 km) all book through the same Maisons de Bricourt switchboard — +33 2 99 89 64 76 — that also takes the restaurant booking [2]. Stay on-site and the taxi line item disappears; the Ferme du Vent “kled + dinner” package at €590 puts the whole evening on one bill [3]. Saint-Malo taxis switch to tariff B from 19h00 (+~50% per km), so the calculus for character-lodging in Hôtel Elizabeth or Castelbrac needs a €70–€85 return baked in [4].
The 30 km circle is unusually dense, but two villages do double duty. Cancale (4 km) and Saint-Malo intra-muros (10 km) appear in both the lodging and activity layers — meaning a daytime visit and an evening sleep can co-locate, but the dinner geometry still pulls back to Le Coquillage. The Roellinger family also runs the Cancale daytime ecosystem itself: Grain de Vanille (pastry, closed Tuesdays), Épices Roellinger at the Maison du Voyageur, Le Bistrot de Cancale above Plage de Port-Mer, and the Cuisine Corsaire École [5]. A weekend can be entirely “Roellinger-shaped” without contrivance.
Two timing constraints contradict each other. The activities child flags three tide-gated sites — Fort National, the walk to Grand Bé, and Mont-Saint-Michel’s “island again” spectacle (which needs coefficient ≥ 110 and only gets close on 17–19 April 2026 in this calendar year) [6] [7]. The IT-conference child finds the opposite cluster: the dense academic window (PQCrypto, CPS-IoT Week, RTAS/SenSys) ran 14 April–14 May 2026 at the Palais des Congrès [8] [9]. If a future trip is date-flexible and wants both spring tides and ambient tech-conference energy, mid-May is the only slot that overlaps. As of 28 May 2026 all of it is already past — the next upcoming tech anchor is Digital Benchmark on 28–29 September, an invitation-only executive format rather than a drop-in [10].
What is not in the synthesis. Dinner mechanics (current tasting-menu price, wine-pairing supplement, dress code, exact reservation lead time, whether the table books in a single transaction with a room) were specified as a verified constraint feeding every sub-topic but were not deeply researched beyond service end time and the shared booking number. Call +33 2 99 89 64 76 to confirm — it is the same number for table and room, which is itself the operative fact [2].
The sharpest open question for the traveller, then, is not where but when: a date-flexible booking in 2027 should target the mid-May tide-and-conference overlap; a date-locked weekend this autumn should pre-book Château Richeux before the restaurant, because the room is the scarce resource [11].