Most of first semester business is in buildings 1, 2, 3, 4, 6 (IIRC). They're all very close, so you shouldn't worry about timing. We'd sometimes run over to Maccas to get a bite in between our no-gap classes =D. I quit that half of my degree after the first 4 subjects, so I'm not sure where you go after that. If you have to be at Haymarket, just plan a pre-walk there and find the room you'll be in (which should be released by mid-February). Honestly, though, the tutors know most students aren't at Haymarket all day, and have no problems with you coming 5 - 10 minutes late. Any later is generally frowned upon, though.