it's just a bit too far walking wise if you're carrying bags. I assume you're arriving at Central? quickest way is probably to come out of Glasgow Central via the Argyle Street entrance (down the escalators on the R/H/S of the concourse as you face south), turn left under the station and make for St Enoch underground (which will be on your right), then take an underground train to Hillhead - Hillhead station is on Byres Road, walk north & Grosvenor Terrace will be on your left after about 5mn, just before reaching the main Great Western Road.