On beer vs ale:
"Turkeys, heresy, hops and beer
Came to England all in a year"
Can't speak for the hops and turkeys, but "beer" as a word was being used in England during the Dark .Ages It derives from the Old English word for barley and can be found in many English place names - Bere Regis etc.
The earliest quote I know of refers to the drink called by the gods ale and by men beer. Ale and beer were originally synonyms - and in Britain, at least, still pretty much are. Attempts are made to draw a distinction between the two styles, but in reality any such distinction is fairly academic, at least as far as the Great British toper is concerned. If you go into an English pub and ask for a beer, chances are you'll be served something warm, flat, brown and very tasty. If you want a glass of overly chilled, pasteurised, tasteless, fizzy piss-water, you'd have to ask for a lager.
By contrast, if you ask for a beer in Canada, Australia or the US, you'll almost certainly get a glass of overly chilled, pasteurised, tasteless, fizzy piss-water.
Joking aside, I think that "beer" is now used to describe any alcoholic beverage made from barley, whereas ale is now used to describe a particular kind of beer - to whit, real beer*.
On the OP, I believe that many inns originally started out as monastic establishments for the succour of travellers. Little places had beerhouses or alehouses - as others have said, often a front room in a private house. Many alehouses sprang up because a particular woman was very good at brewing beer. One or two surive to this day - including Eli's in Huish Episcopi and the Defford Cider House in the Cotswolds.
Regards,
Peter
*Graham's Guide to British Beer. Visiting Britain? As well as enjoying sodden fish and chips in a force ten gale or trying to understand the rules of cricket as explained by a mentally suspect retired major in a white fedora, you must seek out a pint of one of the following brews: Batemans XB, Timothy Taylor Landlord, Wiveliscombe Exmoor Gold, Fuller's London Pride, Golden Pippin Copper Dragon, Moorhouse's Black Cat, Harvieston Bitter N' Twisted, Sharpe's Doom Bar or Hawkshead Bitter.