Summary - The trailhead for Bells Mountain (45.79834, -122.40197) is about 45 minutes from SE Portland, the hike is an easy 650' climb on a rock-and-gravel road, and 2M contacts into Portland and Vancouver are possible with a half-wave whip. The view is open; you can see downtown Portland and with trees on the bordering the clearing, it is easy to get a wire into the air. A great "first season" summit. A Northwest Discover Pass is needed to park at the trailhead.
TL;DR - Bells Mountain is a forty-five minute drive from SE Portland, all on paved roads. The drive ends at BG-2000, which is gated ((45.79834, -122.40197). Google maps will give you good directions. There is a large area for parking and Northwest Discover Pass is required. The 1.6 mile hike up is a gentle climb of about 650' along a forest road paved with chunky rocks. The summit has a microwave comms facility and has been clearcut. Pick a spot along the border of the forest and you'll find plenty of trees from which to hang a wire. I set up SW of the microwave tower, where I had a view of Portland and an enormous stump for an operating position.
It was possible, most of the time, to spot myself using ATT cellular. APRS echoes and two way messaging also worked well. I spent most of the morning on HF but making 2M contacts with a just a half-wave whip wasn't hard. The summit was RFI quiet, with no appreciable interference on 2M or the HF bands.
Overall, an easy-to-access summit with an easy, if boring, hike and a nice view. This is a good choice for a "first season", mountain bike, or "i don't have much time today" activation.