Yeh, unfortunately the parking is only for the Borough residents only
... If you choose to live in the Twp, Summit is a good option, it's a quick drive, and since the Summit train station is a hub, getting a midtown direct train is easy (express trains). The drive to the Summit station - it all depends on what part of the Twp you live in, but generally less than 15 minutes. The down side of parking at Summit is the cost - $10 a day. Many opt instead to drive to either Millington or Berkeley Heights (parking permits are available
Millington is ~$200/yr and BH is ~$220 per quarter for non residents)
Plenty of parking available at the Morristown station, so that is an option as well. (~$85/mo uncovered and ~$100/mo covered for non Morristown residents). Best of luck!