110V AC & 12V DC layout plans

You can daisy chain multiple lights together as long as you do not overload the circuit. And with LEDs you probably would not. But I would still put them on multiple fuses.

You're missing a receptacle in the shower area. Make it a GFCI, same with the exterior receptacle, GFCI. I'd also suggest to add receptacles to the kitchen counter area, you could mount them under the counter top.

Tip: Get a load center that has more breaker spaces than needed. Distribute 120 V through multiple breakers with some devices on their own breaker like fridge, converter, AC, and the GFCI locations. That way, if one device goes South or one GFCI trips, you won't lose power to other devices on the same circuit.

Second tip: No matter if you connect lighting through one circuit or distribute through switching/breakers, use two wires for both phases of 12 V. Do this for all 12 V wire instead of using the body/frame as the (-) phase. Yes, it's more wire but you'll thank me later when you don't have erratic ground issues.

Remember: For 120 V power in an RV, ground and neutral are separate in the load center. Ground should be affixed to truck frame.

Whole rig power selection between generator and shore power can be as simple as moving the connecting shore plug to the generator or using a transfer switch for a mounted generator.

You should have your lighting on at least two circuits. You want to minimize the possibility of being completely in the dark if you blow a fuse. Also balance your loads on the 110v side. Example-I cannot run a small space heater in the bedroom and turn on the coffee pot at the same time because they are on the same 15 amp circuit. DW cannot use her hairdryer tor the same reason. In this case two GFI circuits would be nice, or maybe three. Yes-these are heavy loads, especially with 30 amp service, but principles are the same. Sorry-not sure if I know how your main 110 will be wired.

I'm ok with wiring 110 AC, if it's like a house.

But 12V DC wiring I'm not so sure, for example, let's say lighting, I have LED lighting so I guess I can wire all my lights to one circuit, but do I run a wire for each light? or do I run a wire from one light to another? like in a house.

Do you have a list of electric items that you will have along and a good place to plug them all in?

Toward the rear consider an outlet on each side to minimize a trip hazard to use both sides.
Same with having an outlet near the microwave to avoid draping a cord across. Or maybe there is no space there... would you have anything in the cab area that needs 120v?

Just trying to keep the walkways clear.

Maybe an inlet near the generator. This will make power easier if you want that 5000 btu running in transit.

quick note : it's a 5000btu air conditioner and not 1500btu