One thing to make sure of too, like I mentioned above, is even though it may be legal to carry your firearm into another state while locked up per Federal law, that Federal law doesn't supersede State laws on the type of guns allowed. For example your AR-15 may be perfectly legal to carry around in most states, but cross the state line with it in some states and it's a felony. Same with high capacity magazines, and silencers.
Here is one more thing to be paranoid about, some states have mandatory sentencing laws for illegal carry of a firearm. I think New York is one of those and I don't know all the others. So if you take your chances and carry into New York in violation of their laws, and get caught with that weapon you may find yourself doing six months in jail regardless of the circumstances. For example, what happens if you get in an accident and are injured and the weapon is found while the emergency workers are cleaning up the mess? What if your RV catches fire and it's located that way? What if a situation arises and you have to display or use it? Just something to keep in mind if you chose to ignore the laws.