Monza is well connected with Milan by train (from Garibaldi and Centrale stations) and by ATM bus line 723, 724, 722. Both train and buses arrive very close to city centre. To come to Monza by car from east or west you should take A4 highway (Turin-Milan-Venice) and exit "Monza", from north the Milan - Lecco expressway which ends in the town. From south you'd better take Milan's "tangenziale nord", which starts from "tangenziale est" and Monza exit.
A walk thru the Parco di Monza, you'll understand why Monza people love so much their park. Very crowded during weekends.