This must be one of the most unique questions posted in my opinion. Because of it uniqueness it will require an innovative solution.
Since a 5th is mobile, you will want to use an Amorphous thin film solar panels. These panels are flexible and virtually indestructible.
- On a recent project of mine, the roofing contractor had installed screws through 14 of this type of panel shorting them out.
- To our surprise we found out, once the screws were removed the panels they still functioned producing electricity.
- The other advantage of these panels is their peal and stick installation method design to be adhered to painted metal.
For the proper installation and integration of these solar panels on your vehicle, I would consult with professionals in the marine industry. These solar panels have been used and in conjunction with battery charging systems and dock side AC power for years. I believe that your situation is very similar and will benefit from the advances made in marine electrical charging and battery system industry.
As for the comforts of home look at using DC power rated appliances. This will reduce any energy loss due to conversion from DC to AC. You will be able to use power generated by the solar panels directly and also use the power supplied by the batteries directly.
Sustainable interior finishes
"Green" . . . lets start off calling it what it really is and that is "Sustainable." I believe strongly in using this terminology because you are making a conscious decision to ethically rebuild your 5th wheel considering the environment, economy and the impact on society.
For interior finishes, there are many manufacturers for commercial and residential buildings which can be incorporated in your vehicle. Since the vehicle is mobile you'll want to verify fire rating standards associated with the Department of Transportation.
Thinking sustainable, look at products which do not contain urea formaldehyde, and does not contain Volatile Organic Compounds (VOC), which contribute to off gassing. Product manufacturers have on line their products Material Safety Data Sheets (MSDS). The MSDS reports list all associated health hazards, VOC and chemical make up for each product. This information can help you in deciding whether the material is safe and whether you will implement it in your project.
I wish you much success in your ambitious endeavor.