I'm using Moodle 2.8.9 (20151204).
As the instructor, I can go to:
Home > My courses > Miscellaneous > Course101 > Participants
Looking at the "Last access to course" column gives me the information I want.
I'm trying to find this same information via the api, but I'm coming up short.
I expected to see this via the "core_enrol_get_enrolled_users" web service function. However, I only see the site (LMS) last access date, and not the course last access date.