About 60 kilometers northwest of La Siberia on RN 40, midway between RP 29 and RP 25, an eastbound dirt road drops into the Río Chico marshlands, dotted with birds that include upland geese, coots, and lapwings. Sheltered by densely planted trees, La Angostura has seven comfortable guest rooms (US$90 s or d with breakfast), but also a decent campground (US$10 pp) on a farm that leans toward the rustic end of the estancia continuum.
The food is heavy on Argentine standards like milanesa. Estancia La Angostura (tel. 02902/49-1208, estancialaangostura [at] yahoo [dot] com [dot] ar) is open mid-October–April. If RN 40 is rerouted to Gobernador Gregores , this will be an off-the-paved-track place to experience the old highway.
North of La Angostura, the 200 or so kilometers of northbound RN 40 to Bajo Caracoles  is almost service-free, especially since the owner’s death forced closure of the landmark Hotel Las Horquetas, an out-of-the-wind dive near the junction with westbound RP 37. Some campers like the free sites beneath the bridge over the Río Chico near the junction of RN 40 and RP 25, but the best spots go early.