Can you just smoke weed, enjoy the music and not talk to anybody? Is that sort of experience possible?

Every sort of experience is possible.

You could spend the entire week high as a kite, biking around and just looking at everything without talking to anyone, though the vast majority of the community are people you probably would enjoy interacting with. I find most burners thoughtful, compassionate, playful, caring, etc.

What I suspect would happen is you'd start out this way ^, but then you'd gradually discover that the community is great and interactions with people are pretty fun actually. Part of the experience is the opportunity to get outside of your normal baseline personality if you want. You can be anyone for a week. Most people don't even want to talk about their lives off the playa.

Culture changes on the weekend, when you get a lot of "partiers" just for the man and temple burn. There are a bit more irresponsible and inconsiderate people then, but not enough to ruin the overall community vibe.

You can, but a big part of the marvel is in walking around (er, biking) and seeing the spectacle. If it's your first year, that's your job: be the audience.

Smoking weed is iffy; lots of federal cops out here looking for it, since pot is still illegal on federal lands.

Just chilling and doing your own thing is certainly doable.

Sure, but you can do that at home too.