Finding the site: I-40 Exit 0 and the old roadbed
Glenrio sits at the easternmost exit of New Mexico's I-40 (Exit 0 westbound) and the westernmost exit of Texas's I-40 (Exit 0 eastbound). The exit is shared between the two states and is signed for "Glenrio." From the exit, the old Route 66 roadbed runs roughly parallel to I-40 to the south, and visitors drive a short distance along the old road to reach the main ghost-town pull-off area. The old roadbed is paved but in poor condition; drive slowly and watch for potholes and uneven surfaces.
The main pull-off — where the NPS interpretive kiosk is located and where most visitors park — is roughly central to the ghost-town strip, with the Little Juarez Diner visible to the west and the Texas Longhorn Motel bungalows and the famous sign visible to the east. The half-mile walking circuit from the pull-off covers essentially all of the surviving structures. Parking is informal — pull off the old roadbed onto the gravel shoulder, leave room for other vehicles to pass, and avoid blocking access for any maintenance or law-enforcement vehicles that may occasionally pass through.
Cell phone service is generally available at Glenrio (the I-40 corridor has reasonable cellular coverage in this stretch), so GPS navigation works reliably for finding the site. Google Maps directs travelers correctly to Glenrio if you search for "Glenrio, TX" or "Glenrio ghost town." The site is not behind any gates and there are no opening hours — the old roadbed is technically public and the surrounding structures are visible from public right-of-way 24 hours a day.