From the Avery Point side there are two advantages from launching from here one because it is only a five minute paddle to the waves on the outer edge of the two islands and two you dont have to deal with as many people. Due to the fact that there may be some break on the outer edge of the island this could be a bad choice for beginners.
I personally have found it to be more of an afternoon paddle and personally like to hit the outer edge of the islands and the bluff point beach due to my recent attempts in surfing waves with my kayak. I would caution anyone who wants to try this due to the sharp jagged rocks near the shore.
I you op to try the easier of the two areas I would also launch from the Avery launch site and paddle toward the airport and inside the small rip that is here. This will bring you into a small salt pond where many striper fishermen fish and out going tide in the evening you may also see some chiggers along the muddy bottom on the park side (one an interesting note this is where the Armistead was partly filmed on the outside exposed shoreline of Bluff Point). There is also the lighthouse at the mouth of the Thames River which only looks like a 3/4 mile paddle out I have not yet attempted this but it does seem risky.
There is a porta-potty at the bluff point launching area (no water or showers, sorry).
None from the boat launch at the Bluff Point or the Avery Point launch area.