Plenty of water around Northeast if you know where NOT to go [:-magnify][:-captain]. Get a chart and a sounder and you'll be fine. Most of the skinny areas are mud or sand so "mistakes" just damage your pride, not the boat. There's many other nearby areas just waiting for exploration, too.
I agree with Panther about boat size. I started with a 15' outboard and just going around Turkey Point was a challenge due to all the boat wakes. When we moved up to a 23' cuddy it suddenly became no big deal to run down to the Sassafras, Fairlee or Baltimore. The larger boat was also much safer for our little one.
A smaller boat (or even a pontoon) would work OK on nice weekdays but the weekend will be choppy and it'll get uncomfortable real quick. If you're serious about moving up, spend some time walking the marinas and see what kinds of boats others are using.
Rob