I have always favoured having floorplans on a side table.
That way the building doesn't have to come apart AND
you can vary the interior from game to game (e.g.
game one = one big room, but game two = several small rooms)
It keeps the games fresh & stops (some) gamesmanship, such as
the player who 'knows' the quickest route through a series of buildings
even thou they are playing a different character in a different town.