Citibike is your friend. Jersey City is really big and while Journal Square can feel very dissimilar to NYC, downtown JC and Hoboken are pretty cool and only take 10-15 minutes to bike to.

Also, splurge and get a monthly parking spot if you can. You may be able to find one for $150-$200 a month and let me tell you, you will appreciate it in the winter. You'll get hours of your life back every month.