Sound Transit recently released an updated animation video of the proposed Lynnwood Link light rail route from Northgate to Lynnwood. See the video embedded below, the Mountlake Terrace portion starts at around 3:30. Approaching Mountlake Terrace from the South, an elevated light rail will come up the east side of I-5 along the back of the Freeway/Tourist zone in Mountlake Terrace. As it goes next to the old Evergreen Elementary property, the plan is to have the elevated light rail tracks parallel the future Gateway Boulevard and cross over 236th. The animation shows the 236th St SW station will be elevated partly over 236th and mostly over the existing Transit Center surface parking lot.
Heading north from the Transit Center, the elevated tracks wrap around the parking garage to the west and crossing I-5. The current preferred alignment is to have it then travel north on the west side of I-5. The tracks would then dive down and cross under the 228th bridge at grade. The tracks continue north and then become elevated again as they cross 220th on the west side of I-5. There is a potential 220th St SW station which may or may not be built. It's still unknown if the 220th St SW station (as well as the 130th station in Seattle) will be built with the initial Lynnwood Link construction. If construction costs come in low the station could be built, otherwise the tracks would be built to allow for construction of the station at a later date.
The preferred alternative route head north from 220th elevated, drops down to at grade level and then is elevated crossing 212th St SW as it leaves Mountlake Terrace and on in to Lynnwood.