Lucasfilm

Life advice from a fellow Star Wars fanfic author: abandon hope all ye who enter here. They won't take any submission of any kind, so your best bet is to just put it on the internet and get it out there that way. My book, Snoke: A Star Wars Story, is available at snoke.home.blog. Building the site was free so it's a good first step. Best of luck to you, I know how it feels.

C-3PO but not even a replica R2D2

If you know someone that works there they can take you on a tour of a bunch of areas, but they have to escort you the whole time.

There's a large-ish campus and a starbucks in the compund. You can potentially walk around as long as you like. There's a Yoda fountain in the compound. The lobby has amazing statues and originals / replicas of the light sabers used by Yoda, Luke and Vader. But beyond that, it's just offices where people work (or so I was told by the front desk lady). There's (sadly) no gift shop.

I'm in the same boat. I wrote a book but Lucasfilm won't take any submissions except in extremely rare cases. But if anyone wants to read my Snoke book they can do so at snoke.home.blog.

No. This is a working location. There's a lobby you can walk in and look around, but that's it.

The park of the facility, yes. During the opening hours you can also go in the lobby which has a lot of star wars related items, otherwise, no.