We have our boat on Barnegat Bay on Forked River now and used to keep it on the Delaware River at G. Winters Marina in Riverside.
Denise was right. You will need bottom paint
if you stay in a slip in either location. But you'll need different paint
for the river vs. the bay.
They're two VERY different sailing destinations. Currents are strong on the Delaware and we liked sailing on weeknights or early morning on weekends before all the powerboat A$$!!*^#'s came out and started throwing big wakes. It can make for confused wave patterns that might not be fun in a light 17 footer. That said the river during quiet times is really nice. My last sail there was a mild day in late October. Just me an a lot of migrating ducks on the water. Beautiful.
For us the Bay is better sailing. Larger, more varied, more places to sail to and some dock-n-dine locations. More boat traffic on weekends but not nearly as congested as the river can be.
Traffic to the shore is not bad if you're in a mainland marina as we are. We're near the Cherry Hill mall and it takes us an 1:15 door to door. We kept our boat on LBI for two seasons in Beach Haven. That was an 1:30 early morning and could be near two hours once shore traffic got going.
I don't remember the Newport 17 having much in the way of live-aboard accommodations so I'd think you'd get more use out of her on the river. If you're out sailing all day you won't feel like driving home from the shore.
If you have a place on LBI in September you could trailer her down and launch from the ramp at 12th street in Beach Haven. You might also be able to do a 1 month deal with the Beach Haven Yacht Club or one of the marinas up by the light house depending on where you are on the island. From most of the island you'll be sailing in Little Egg Bay which is much shallower than Barnegat Bay. If you're in a marina up by the light house you'll have access to the lower Barnegat bay. You could also talk with Rich at Mariner's marina in Barnegat. When you come off the island make a right on Rt 9 and it's about 15 minutes to Mariner's marina.
Best of luck whichever way you go,