10:15am: Meet at rose garden gift shop/restrooms (see map below)
NOTE ABOUT START TIME: I'm starting this crawl 15 minutes later than usual due to limited public transit options in the area; see transit/parking options, below.
Nearest MAX stop would be King's Hill, not the Zoo; from King's Hill it's a ~14 minute walk uphill to the park entrance at SW Park Place; from there continue another 10 minutes uphill or wait for the free shuttle which runs every 15-30 minutes starting at 9:30.
Parking is in demand in Washington Park; there may or may not be spaces available near the Rose Garden.
The Rose Garden is NOT near the zoo, for walking or shuttle ride purposes. I say that for people like myself who tend to underestimated the size of Washington Park!
Unfortunately Trimet Line 63 doesn't start up until 10:25 but you might choose to utilize it on your return trip.
Washington Park Map
TriMet Line 63