I have two excellent resources for designing inns. My cartography skills are exceptionally weak (my major projects were in my youth with graph paper and pencil, computer would have meant designing it in ascii )
The resources themselves will also give you an idea of that, BUT these are EXCELLENT.
1. The Compleat Tavern by Gamelords (used on amazon for $20) is 24 pages and is chalk full of things about different size fantasy taverns, games, drinking, wenching, etc. But it really gives a lively idea of a tavern and things that a good tavern should include at different levels.
2. Cities by Midkemia Press ($26 Amazon) had 2 pages on Taverns but it was also pretty good and did an excellent job of telling what was usually around different size inns and cities. I would recommend it for any fantasy community cartographer actually. I think Chaosium reissued this later, but I'm not sure it included the tavern table. (I can't find my copy).
3. Any of the Citybook series by Flying Buffalo.
I think if you picked up the Compleat Tavern you would really feel your taverns come more "alive", just like I did back in the day. The reason is that I would roll up a tavern with all the people, services, patrons, amenities, etc, then I would try to figure out how all these people would fit in, then 2-3 more times I would roll up different patrons and see if they still all fit 80% of the time. Inns might actually be bigger than you might think. The reason is that for a small one you might have to think of it like a small town restaurant. In the morning everyone is sitting at "the bar" but at night more people use tables, then slowly, back to the bar. If people play games, will there be room for them? Just things to think about.
I wish I had your cartographic talent, as you can tell I'm more analytic myself.