Replacing lower HappiJac bunk with Sofa or dinette

We bought some queen sized air mattresses for the Happi Jac beds to make them more comfortable, and still be able to use the dinette in the back. The kids like to use that table to play games and occasionally eat dinner. I installed a 12 volt plug back in the garage (can't believe they didn't put one there) and we use a portable inflator to blow them up. When they are deflated, they stay flat on the top bunk for storage.