The original (2005) edition of Mike Coltrin's Sandia Mountain Hiking Guide noted that as of 2001, the road to the Cañoncito and Bart's trailheads was closed to vehicle traffic but that "The private landowners currently allow hikers to walk up the road to the trailhead." As the new (2019) edition acknowledges, this access option no longer exists. Instead, the private land is posted, and the fine print makes it clear that there's no exception for people on foot. 

At this time, the closest developed access points for Cañoncito and Bart's (and the southeast Sandias in general) are at the Cienega Canyon picnic area and the south end of the Crest Trail. Between those, the Casa Loma Route begins at an undeveloped access point and links to the Faulty Trail.