There are plenty of trees from which to hang a bag but a lot of people (myself included) didn't worry about bears except for certain sections, so we didn't bother hanging a bear bag. I think squirrels and other small scavengers were more of a threat than bears in many places. I kept food in a large silnylon bear bag lined with a odor-barrier OPSack and called it good, often sleeping with it under my head when a convenient tree wasn't available. I didn't carry particularly odorous food.
A lot of people carried Ursacks and others carried cuben or silnylon bear bags and slept with them or hung them if need be. ZPacks makes some as well as others. Just a big sack with some spectra cord and a D-ring carabiner.
The possibility of bear interactions are greatest in certain spots in the Sierra, although we encountered bears in Southern and Northern California as well as central/northern Washington. The truth is, the greatest population of bear activity you are likely to see on the trail is when you walk near established (car accessible) campgrounds, which are fairly rare. The one where you would see bear activity if you hung around for a bit would be at Yosemite National Park adjacent to the Tuolumne River, aka "Blue Plastic Tarp World." You walk across some of the most majestic passes in the Sierra and then the trail descends to travel near that place, and it's a bit surreal. But the bears know that the campers there have coolers and food, and they are very familiar with humans. I'd suggest moving on and camping say, a couple of miles north.
You will have a great time. I am confident of that. It sounds like you are very prepared and are asking all the right questions. If you haven't seen it before, the pct-l (List serve) is another great place to have questions answered, although it's not the most organized forum on the Internet.
Enjoy your adventure! Keep the questions coming, there are many PCT/Long trail veterans on these forums.