The Inn is widely known to a select few. It has a will and a consciousness of it's own and has been around for as long as any can remember. It shows up, coming and going on its own, in this world and maybe in other dimensions. When it arrives in a location, all the locals remember it as having been there for years, and can give directions to it. When it vanishes, all the locals remember the location as housing some other building that was burned down, or razed, or something. (The Inn? Sure, it's right over there, around the corner. Been there for generations. // The Inn? Never heard of it. Over there? No, that lot's been vacant ever since Charlie's Warehouse burned down last year.)
The Inn will not allow Evil creatures to enter. Evil creatures will feel a very strong disinclination to enter. If they persist, they will experience a constant drain to EGO, WILL or something similar and a continual telepathic order to "Leave!". (The Inn can allow Evil to enter if it suits it's purpose, but that is exceedingly rare.)
Likewise, the Inn can make it's needs known. It will phase in near an adventurer that it would like to recruit. Adventurers meeting the requirements will get a restless urge to wander, looking for they know not what, and wind up at the Inn. If they decide to join, fine. Otherwise, the Inn keeps looking. The Inn does not seek out particular people; in fact, it is doubtful that it really comprehends people as self-willed individuals.
When the Inn is about to move, anyone in the Inn who is not privy to the Inn's secret will suddenly get the urge to leave. (Well, folks, time for me to be going home.) Likewise, those not privy will not be allowed to rent a room here. (Sorry, sir. We are full up. Try the hostel down the street.) Although the Inn has only two stories visible from the outside, the stairs going up do not stop at the second floor, but continue up as far as necessary.
The Innkeeper, who calls himself Lennie, is an elderly man of indeterminate age. He is very wise and a very powerful magic-user. He is very oracular, rarely answering questions with anything but another question. Speculation is that he is one of the Wizards of the Gate, the ones that made the Gate and warned the Peoples of the coming disaster. Other speculation maintains that Lennie is actually a metallic dragon or a demigod. He neither accepts or refutes any of these speculations. He says, "I am as you perceive me." Some refer to Lennie as the Master of the Inn, but he maintains that he is only the Inn's hired help. He does respond more favorably to Sensai, or Teacher.
A brotherhood, called the Brotherhood of the Wild Geese, has developed around the Inn. It is very loose, but those who are in it have been vetted and are more to be trusted. Others can join on adventures, but may be viewed with some distrust by members of the Brotherhood.
Dimbold the Gloomy, handyman
Dimbold, age 43, looks to Lennie as a combination older brother and father. He isn't too bright, but is very willing, despite his sad eyes and gloomy disposition. During the day he helps in the garden and around the Inn, doing most of the heavy work. At night he works behind the bar. He is married to Fat Gertrude, the cook.
Fat Gertrude, cook
Gertrude (age 39) is a jolly, happy lady who loves to cook. She is motherly towards those younger, and a cordial friend to those older. She has no enemies, takes a happy view of everything, and is impossible to hate. She spends most of her time in the kitchen, cooking or puttering. She is married to Dimbold the Gloomy.
Edna and Ludmilla, chamber- and scullery-maids
Edna (age 25) and Ludmilla (age 60) assist Gertrude in the kitchen, clean the rooms, and take care of various indoor chores.
Edna is an orphan who was being cruelly tortured by the locals of her area because the daughter of the village headman had turned sick and Edna was accused of being a witch. Lennie does not talk about it, but rumor has it that there is an area where the fear of magic-users is very fresh and very real. He rescued her, healed her, and gave her a home. She is very shy, worships Lennie, and anyone who is kind to her will win her loyalty.
Ludmilla is a pleasant but slightly senile person who mothers everyone. She is well-meaning, but always manages to show up at exactly the most inconvenient time to do some minor chore in exactly the most exasperating manner.
Selene Lightfoot, serving maid
Age 26, Selene is a beautiful but practical girl who's parents were poor peasants in a backwater hold. She ran away to seek her fortune. She serves in the common room or upstairs, flirts with customers, dances with sensual abandon while accompanying herself on the tambourine, and radiates sex appeal. She has great ambitions and is always lured by money. Selene is pragmatic, spurns romance, and will freely sell herself for a night to a guest if the price is reasonable. She affects a happy-go-lucky "bird brain" attitude, but it only takes a short chat to see she's brighter than that.
Hultz (age 30) was kicked in the head by a horse while a child. He has grown up to be a very slow thinker whose attention wanders. He is very strong, very gentle, lives life in a daze and everyone knows he is "without his wits." He has been the Inn's stableboy for the last twenty years and has a very gentle hand with animals. It is hard to get him riled, but cruelty to "his" animals will do it every time, and he will wade into battle, fists flying, bellowing at the top of his lungs. His great pride is his rock collection, and he may ask travelers if they have brought him a new rock.
Whenever the Inn is about to move, Hultz will come inside and sit by the fireplace with his arms around himself; otherwise he stays in the stables. If asked, he will just say, "It's gonna move. I don't like it when it moves." It may be in 5 minutes, or it may be an hour, but he will sit by the fire, scrunched up with his arms around himself, until suddenly he'll get up and go back outside. The Inn will be in another place, although no-one else can detect any sign that it is going to move, is moving, or has moved.
We use the Inn in my campaign as a sort of base for our characters, since we are all over the world. It doesn't get too powerful, since it is GM-controlled, but it cuts down on all the excessive wandering that we would otherwise have to do. The Inn just drops us off where it (ie the GM) wants us to be and we trek on in to wherever we need to be. Works for us.