Directions (From Portland, ME): Take Rt. 302 North, through North Windham and through Raymond. After going through Raymond Village you will come to the intersection of 302 & 121, stay straight. Sebago Lake (Raymond Beach) will be on your left. At the next point on 302, where you are crossing water, is Thomas Pond. (Maybe about 3 miles beyond Raymond Beach.) Launch site is on the left of 302 when heading west/north.
Boat Launch: To launch here, there is a wide shoulder along Rt. 302. People put in on the southwest side of the bridge. You can paddle around in the area where you launch, but will hit a dead end. Then to access Thomas Pond go under the bridge and just keep going. The beginning part of this paddle, from Rt. 302, will feel like you are on a small pond, but it opens up to a very large pond.
There is also a very small hotel on the right side of Rt. 302, across from the boat launch. They may allow people to launch from there, but I am not sure.
*I usually launch from the camp of one of my friends. I have not launched from the side of Rt. 302, but have seen people launching from there.
This is the boat launch, on the left of Rt. 302 (Heading away from Portland):
Parking: Free. There is a small place that looks a bit like a driveway where people launch from to leave vehicles. Limites spaces, but again, the small hotel just ahead, may allow people to park there.
Wildlife: Turtles, Loons, Ducks, and canada geese. (My friend's sister claims she saw a moose early in the morning!)
Notes: Pay attention to where you come onto the big part of the pond, so you know where to return to get back to your vehicle. There are a few places that look similar. I find paddling along the shore in the same direction will eventually get me back to where I started from. Thomas Pond is a good size pond to paddle around the whole thing, very enjoyable!