US 66/US 89 continued east from the SR 64 junction outside Williams on Mountain Man Trail for , then crossed the present-day route of I-40 diagonally onto Deer Farm Road. Although the highway was paved in 1940, both Mountain Man Trail and Deer Farm Road have been downgraded to county maintained graded dirt roads. The highway skirted the northern shore of Davenport Lake, then crossed present-day I-40 to the south side frontage road, known as Mountain Ranch Resort Drive. US 66/US 89 crossed I-40 a second time at the spot of the current exit 171 onto a road called "Old Route 66". Unlike Mountain Man Trail and Deer Farm Road, Old Route 66 is still paved. The highway then headed east, gently winding through small pine forests, until US 66/US 89 reached the town of Parks. Small sections of Old Route 66 to the west and east of Parks are listed on the NRHP under the name Abandoned Route 66, Parks (1921).