If memory serves me correct the frame height is 17" +/- hit me just below the knee. I added a 15" cabinet and with the top the counter was 35" approx.
Pehaps a flop out floor with freestanding legs to the ground with the dining room under the floor might be a better idea. Make a great dining area or with side curtains a privacy changing room or storm proofing for the dining area. When closed the clam shell could provide some storage if built with a little depth to the floor as shown below
http://tnttt.com/VintagePlans/foldingbedroom.pdf