Salmon Fishing

The only sure way is to ask Canadian customs, and US customs. If you get a border agent who is a hard ass, things will be different than if you get someone else. Are you freezing or canning the fish? Your limit will be per person, so you better be able to identify which person a particular fish belongs to. Label them, canned or frozen, with someone's name and a date, caught or preserved, either one. If they are frozen they need to be frozen hard when you cross the border. That first agent I mentioned might use the splat test. They throw a fillet on the ground and if it splats it's not hard frozen, and therefore not preserved. It will count toward a daily limit. You need to leave the skin on the fillets so they can be identified as sockeye. this applies to canned or frozen. You may have your daily and possession limit according to Alaska regs, which change annually, and whatever someone tells you now may not be accurate when you are there. It should apply on the day you caught the fish, so make sure they are dated. The limit on reds often goes up or down as the run strength is known. So what I was wondering is how big a freezer you have in the rv, are you thinking that a cooler will work? You want fillets or whole fish? (border security prefers head on, but I don't think that's a law.) I've crossed many times with many fish, just coming from BC to WA. Often they don't even look or care, but then there's that one guy who does. Border security on this kind of thing, fish, seems to be more strict for US agents the farther east you go. The guys at the AK/YT border deal with this many times a day, getting back into the US you are more likely to encounter an agent who is not as accustomed to it.
Oh, and make sure you have you license with you even if it no longer valid.

The easiest way is to either have the fish shipped for you, check out Echo Lake Lockers in Soldotna. And get some of the cheese dip while you're there it's truly world famous, they ain't kidding. Or just take your frozen fish to UPS. Use their fish boxes and they guarantee it will still be frozen when it gets to Maine. Costs not too much and it will still be the cheapest salmon you can get.