I will be in the area in early October and would like to visit a few gardens. Any suggestions?
You should post in the NJ forum but here are a few possibilities.
Atlock Farm is in Somerset. 545 Weston Canal Rd, Somerset, 732-356-3373. It is a nursery with a nice display garden.
Frelinghuysen Arboretum is in Morristown.
Then there is Willowwood which I haven't gotten to yet
Well Sweep Herb Farm has a display garden
There are botanical gardens within a reasonable distance in NY and PA.
NY Botanical Garden
Here is a map at posted by Rutgers Cooperative Extention Center. Not all listed are a real gardener's destination - such as the Pequest Hatchery. But there are a few to look into. New Jersey Botanical Garden in Ringwood would be a drive from Warren but a good day trip too.
Here is a link that might be useful: Rutgers Garden Map
Your post on the NJ forums say Warrenton, not Warren...I am not familiar with Warrenton. What part of NJ is that?
I didn't post there so I wouldn't scrowl it down.