Nobody pulls off the interior skins just to do solar, even the fanciest systems. If you have the skins off for other reasons, sure, you can make things easier.
Solar can be as complicated and expensive as you like. The easiest, as was mentioned, is to get one or more portable suitcase panels and put them on the ground. Be sure to get a suitcase with a controller with at least 100 watts. You can have more than one or get bigger 200w versions if that’s not enough. Renogy
is a popular brand.
Once you decide to put something on your roof and build it into your trailer you can go on quite a trip down the rabbit hole. Mine is a 500w system with 500ah of lithium batteries along with a Victron hybrid inverter and associated electronics. That cost about $10k for the parts, I did the installation myself. www.amsolar.com
has some good videos and tutorials about these high end systems.
Having a built in system with the batteries and electronics to go with it is truly liberating. We don’t have to think about power. We run induction cooktops, hairdryers, tv, coffee makers without a thought. Whether it’s worth it to you is a personal choice.