Changing over to a Goose neck will void your frame warrantee unless you use a Lippert approved Goose neck adapter (Goose Box). We do not offer 1/2 bath options into a garage area on a unit that currently does not have one. I have seen dealers add 1/2 bath's after the fact, but it would be up to the dealer and expensive. Dinettes in place of the Mega sofa is not an issue, as long it is in a Mega slide unit. Units that have a Mega slide in it actually have 3 separate slide-out configuration options. Each unit comes STD with the mega couch that fills up the entire slide out. However if you prefer we also have the option of booth dinette with small couch or free standing dinette with small couch. The units that these options are available on are CYC - 3110, 3800, 4100, 4114, 300C RW- 400, 410, 415, 425, 30C. The only option for lighter cabinetry is our Ivory cabinetry (in kitchen, bathroom, and garage) offered in Road Warrior only. If you have any other questions please let me know.