How many ways are there to get full movement that will allow a character to use acrobatics in order to move through enemy squares?
"Be a dwarf" is the easiest one. "Be a sufficiently high level fighter" is another. Rondelero Duelist works. Metal Oracle's Armor Mastery works in most armors.
Fighter's armor training works.
Emissary Cavalier is notable for allowing you to move full speed in mithral fullplate with only a 1 level dip in the class (you'll want a class w/ Heavy Armor Prof. or spend a feat on it to avoid massive nonproficiency penalties, though).