There are multiple trailheads to choose to park at. Long Lake (road not maintained), Matanuska Lake, Crevasse-Moraine, UAF Matanuska Experiment Farm, UAA Matanuska-Susitna College Snodgrass or MSC Nature Trailhead. We usually part at Matanuska Lake but you need a State of AK parking permit (day use or annual).
Trail maps are shown on the Matanuska Greenbelt website: https://sites.google.com/site/matanuskagreenbelt/
Congratulations to cavyguy on the FTF!