Landlord's post is made of magic and awesome. Right down to the chavs in Wetherspoons (Don't go there, they are just bars) I can't add anything to his post, really, just emphasize that you have to find your own pub there.
It's like trying on a bloody glove in a courtroom. If it don't fit, you must just quit.
I'll leave the beer talk to Landlord, he has it covered. I noticed you mentioned cider a lot. If you are truly interested, then you have to go to Somerset or Devon, and once again, find the pub that suits you. You will need to drive out on the moors and stop at any place that looks remotely like a pub. (I went into a pub there once, and I'm still not quite sure if I was just invading someone's living room) There they will have cider that is not for the refined pallet. Your mouth will pucker up so hard that it sucks in the rest of your head.........The real point is not actually great beer or cider, although you can find both.
The true point of a good English pub is that when you find one that fits you, it fits you like a glove, or the love of a good woman. It may even fit you like a good woman wearing a lotion soaked glove (wink wink)
A good pub will have good beer, even great beer maybe! However, it's the people that make a great pub, not the beer.............So you MUST try them all. If you do not try all the pubs in England, then you are not worthy of your quest.
In short, contrary to what would seem to be obvious, the pub is a little bit more important than the brew. It's not drinking good beer at home, it's a different experience than bars too.