Boots of Swiftness + Zephyr (which has +10% movement speed). Plus it gives him tenacity on top of the swiftness boots, some AD, AS, and CDR. Pretty good all-around for Garen. Then go Phage/FM after that and you become a nightmare to chase/run from. Give it a try!
Sorry, but IMHO you don't want to waste that much stat gold-wise on AS you dont use (that much).
I would consider Reverie an option if you got problems with kiting, and I go Spirit Visage in general vs AP. Else Bulwark, Hex.
I also dont really go Phage/FM for the stat-reason again: I won't do AAs all the time, Spin2Win too stronk.