Fellow Californian here - Sac County (area not jail
)
For your number 6, you should absolutely go to the E4 meet-up if you are willing and able.
As someone who joined the site last year I was a little nervous as I felt like a noob in the collector space compared to a lot of the people who went from here (and rightfully so in my opinion) everyone was so relaxedand friendly whether there were more introverted folks just observing or more extroverted ones making rounds, mingling, and doing various activities. I did the the former and latter.
The passion for the actual hobby and franchise was infectious, yet it felt cozy, never had that feeling hitting local card shows or card shops (I am only a casual/once in a while customer at 2 of mine so that is why).
I was also stoked to be in the same room with the dudes who run Pokebeach (waterpokemonmaster) , Pokumon (Humanforscale) , and Art of Pkmn (Kev) and talk to all of them.
People also had their collection binders and slabs on display for others to browse so that was a gallery in itself.
I would also highly recommend going to Worlds for at least 1 day, if you can get a ticket and are able to put up with the crowds. Full disclosure, I am an ambivert but definitely heavy on the extrovert side.
I had a weekend pass, and picked one up for my little brother from a competitor. It felt nice being amongst so many people who share similar interests in Pokémon whatever part of it they may be into. There was plenty to do and see.
I was, to my surprise, really excited to watch the tcg and vgc matches on the screens and finally understood why people who like watching sports are so into it.
My favorite part had to be the live artist interviews (shocked not too many people went to it), and BB/WF tcg art gallery.
From my Anaheim experience there were a bunch of people but they were friendly and mostly kept to themselves/their groups. A lot of people talked to me but it’s because I always make eye contact with anyone passing by, which really annoyed my little bro (very introverted and quiet dude) 
Trading area was a little chaotic and the store was the most chaotic but even then it was managed well by the organizers/staff and people did not act like animals or push/shove.
With so many people it was noisy, although having been to 3 Aftershocks in a row a few years back, the noise was minimal in comparison.