APRS Coverage
Good digi echos
Voice Cellular Coverage
Good, very usable
Data Cellular Coverage
Good, very usable
Cellular Provider
T-Mobile

Here is an urban 'pavement' activation - the closest one to downtown Portland. The summit proper for Cornell Mountain is on private property with the Activation Zone accessible from a neighborhood street with no shoulders. This summit is near a number of very large comm installations and 2m FM was totally blocked with S9 noise on my Yaesu VX-8G - 70cm FM might be a better choice and HF isn't a good option as there's only a small muddy shoulder spot in the AZ big enough for HF antennas - and that's where you can park. 

Cornell Mountain summit is near 7263 NW Penridge Rd., Portland. One place for parking safely on these narrow roads is on Penridge, next to its intersection with NW Greenleaf Rd. For access from downtown Portland, head up West Burnside Road and veer right onto NW Skyline Blvd. You'll pass the Willamette Stone State Heritage Site and after about 0.9 miles on Skyline, will turn right onto NW Greenleaf Rd and then an immediate left onto Penridge.

The group of mailboxes pictured below with a rock beside it could make for a decent spot to stand for a few minutes while activating this peak.