Hi, I completely understand your situation as I have very long bus rides twice a day. Learning stuff like installing php5 is easy, and the same with extensions, all you have to do is google something like "yum install php5 zend" or "apt-get install php5 zend" and it will give you the exact command you'll be looking for, a lot of the stuff is referenced by server administrators as you won't need to memorise them. I'd suggest if you know Ubuntu try CentOS, if you know CentOS try Fedora.

When it comes to optimising I think that's a lot down to personal preference and it depends on your server. If you have a very powerful server and just want to run WordPress you aren't really going to need to do anything to speed it up. But if you wanted to you can just google "optimise centos speed" and stuff like that, the sentence in the quotes doesn't make grammatical sense but it doesn't need to as google filters out short common words and it only looks for keywords.

I don't really know a lot about configuring firewalls so I can't help you out there. I know of a site that has a lot of useful stuff that robert420 reminded me of the other day:

http://www.howtoforge.com/