This is not a crude anthropomorphism, but an actual theophany. The "Word of God," Christ in His preincarnate state, regularly appeared in the garden for fellowship and communication with His people. How long this period of fellowship had endured is not stated, but it was long enough for the Satanic rebellion in heaven and expulsion to earth. Since it was not long enough for Eve to conceive children, however, and since she and Adam had been instructed by God to do so, it was probably not more than a few days or weeks.

Source:

KJV Defenders Study Bible, by Dr. Henry Morris, Ph.D.
Publisher: Thomas Nelson
Language: English
DEF 10 ISBN 0-529-10444-x
DEF 10-1 ISBN 0-529-10445-8