I just changed the front bunk on my 13' Scamp into a dinette for two. I can still use the front bunks or sofa with this setup. I first cut out the center section of fiberglass using a sabre saw with a fiberglass saw blade (make sure you use masking tape over where you are to cut to prevent chipping). Then I used 5/8" white laminated shelving for the sides (cut to fit under fiberglass for support). I  screwed through the fiberglass into the 5/8" shelving material to hold everything in place. I made the table out of 3/4" white laminated particleboard with iron-on white edging. I made the support rails for the table in the down position, out of the left over white shelving material. All the materials and the saw, were bought at Menard's (except the table base and leg were bought from Scamp) for less than a hundred dollars. I had a friend cut the original seat cushion into three pieces for the new dinette seats (they can also be used for the sofa/bed).