MATC likes to pretend that our state is a wilderness, and doesn't provide picnic tables at shelters -- or didn't the last time I visited a Maine shelter.
But I've made several over the years for picnics, outdoor lobster bakes, and parties at my house, and to give to kids and relatives.
They are easy to make. A basic design can be found here:
http://www.handymanwire.com/articles/picnic.html
My first table used the design then used by Maine Department of Transportation for its roadside rest areas. It's essentially the same as the above. My version has evolved to use only 2 x 6, by 8 foot spruce or pine, except for the 2 X 10 inch seats.
I also moved the legs in so that there is room for one person to sit outside the legs on each end. Aesthetically, it looks better, and makes more efficient use of space.
They are simple to assemble. If you use standard 8 foot timbers, there's only a dozen saw cuts. I use a table saw -- sometimes a chain saw if I'm in a hurry.
After the cutting I use 3/16" by 3.5" lag screws to hold everything together. Drill quarter inch holes first to avoid splitting the wood. The tops and seats are always untreated wood because I dislike sitting on, or eating off chemicals. For the legs, I sometimes use treated timbers.
Weary