updating github.com forks, developing in remote branches and svn:eol-style equiv?

Say on github.com I fork a repository.  Two weeks later, updates have
been made to the original repository and now I want to update my fork.
 How do I do this?

One possibility that occurs to me: I can create a new remote repository - let's say "upstream" - with the URL of the original repository and I can pull from that instead of the forked "origin" repository. I can then push the updates to the forked repository.

Is that the best way to do it, though? It seems to me that I ought to be able to have my github.com fork pull updates itself without my having to pull and push with my own local repo.

Also, I'm unclear how to develop in remote branches. If I go to the "Switch/Checkout..." dialog I can switch to, say, "remotes/origin/random-branch". I do that, make some changes to one of the new files and I then try to push those changes back. In the local drop down menu I only see two local branches, however - "(no branch)" and the default branch. Why is that? If I just switched the branch to, say, "remotes/origin/random-branch", shouldn't I now be seeing that branch locally?

Finally, is there any Git equivalent to SVN's svn:eol-style and if so how do I take advantage of it?