Trying to put together a vacation (for 2 adults) this year, and wanting to possibly include snorkeling...not open water, something a little closer to the shoreline. I am wide open for a destination and time of year, but also want to be able to walk/hike, sightsee, etc. The only other stipulation is limiting it to the contiguous US. Wanting to stay about 1 week and driving or flying from NJ area are both options.

njgirl,
You can try the Florida keys, but that's about the only good snorkeling area in the lower 48 states.

Curious - why limit yourself to the US mainland. You can fly non-stop from Newark to many places in the Caribbean, including the US virgin islands - less than 4 hour non-stop flight.

Guess I was thinking narrow-mindedly that the only other thing there is to do on an island is sunbathe...need more activities, and not into the all-inclusives.

You can snorkel in LaJolla Cove in California/ with lots of hiking and other sightseeing to do close by -

Wade-in snorkeling in the Frorida Keys is negligible. The reefs are 5-6 miles offshore, reachable by boat tours. Best wade-in snorkeling, fairly quick plane ride is St. Thomas or St.John in the US Virgin Islands. You can leave JFK or Newark early AM and be in by noontime. There is a nice beachfront hotel on STT, Secret Harbour, with snorkeling right off the beach. STT has lots of shopping, sightseeing. Or stay on STJ where there are a number of gorgeous beaches on the north shore in the National Park with snorkeling. There is hiking and some sightseeing, plus STT is only a short ferry ride away for a daytrip.
NOTHING on the mainland comes anywhere close to comparing.

Wow, that sounds good...but am I going to need a loan to vacation in the islands? Don't want to blow all my savings.

See www.secretharbourvi.com
You can stay under $200/nite there.

Catalina island off L.A. has excellent snorkling. The water is cold and you need a shorty wetsuit, but the water is very clear and sealife abundant.
The island also offers lots of other tourist activities.

That's a tough one. I would have to agree with xkenx about snorkeling in the keys. I've snorkeled at Bahia Honda state park in the lower keys and saw some lobster, sparse coral, baracuda and tropical fish. Looe Key is an amazing place to snorkel, but it's about 6 miles off shore. Not sure why no open water. It wasn't very expensive when we went about 5 years ago and bonine kept me from getting sea sick. You can get a boat at Little Torch Key (about mm 29). I can't recommend it enough. The experience of a lifetime swimming with every type of sealife imaginable and coral as big as cars. There's so much more to do in the keys besides sunbathing. We've experienced some good snorkeling off shore in St. John's USVI. If you are into camping, there are 2 US run camp sites on St. John's which i'm sure are a lot cheaper accomodations than a hotel. I've been to the one at Cinnamon Bay and it seemed nice. There's a place there to rent kayaks, etc. and good snorkeling from the shore.