AVION Travel Trailers

I have a 1979 Avion 28 ft. type M and am doing a solar upgrade. All of the components except for the service panels will be located under the couch at the front of the trailer. I need to run two strands of 10/2 gauge wire from the service panel in the bathroom (mid trailer above wheel well) to the inverter at the front of the trailer.

I would also like to run 12/2 gauge wire for an A/C circuit to power an 80 amp converter/charger in the same location. I need to move the converter closer to the batteries because the existing 6 gauge wire can't handle the 80 amp output but it can still be used to supply D/C from the batteries to the panel in the bathroom. This circuit is not essential because there is a 110 v outlet by the couch that I can tie into if needed.

What is the easiest way to do this?

I'm sorry, I'm not familiar with a "Type M". What model does your serial number say it is?
120 VAC runs in the trailer should be 12/3 or 10/3 or 8/3 (Triplex) depending on current. DC runs - the wire gauge will vary based on the round trip distance from load to source and anticipated current draw. I refer you to the reference here: viewtopic.php?f=2&t=927

Additionally, pictures of the interior layout would be useful.

On type M trailers the bathroom is in the middle of the coach and the bedroom is in the rear. The installation instructions for the inverter I purchased calls for 14 gauge solid core wire but I was going to go with stranded because its easier to fish. Romex 14/2 actually has three solid core wires because it includes a ground but is only rated for 15 amps. I want to go larger in case I decide to swap out the inverter for a larger one at a future date. Romex 12/2 with a ground would work for up to 20 amps but 10/2 would be best because it has lower resistance and is rated for 30 amps. But the main problem with Romex is that it isn't as flexible as stranded wire.

The issue I'm having is how to run A/C wire from the service panel that is located in the bathroom vanity above the wheel well to the front of the coach. The shower is adjacent to and forward of the vanity followed by the refrigerator.

The D/C wiring isn't an issue because I can repurpose the original 6 gauge wire that runs from the service panel to the front of the coach.

You will want to investigate Ancor Triplex wire.

Thanks for the tip. I'll check it out.