RoyalSubject
Prospect
there was no proof he was in NH all those months, and everyone but the Nazis was completely in the dark about their underground meth lab so Walt disappearing down there while making a trip to NH and maybe getting a little sloppy covering his tracks as the cancer progresses doesn't seem like an implausible front.
Walt's finger prints are no where in that lab except on the mask and his blood smear on the tank. Jesse's are every where. Both are known meth cooks. It wouldn't hold up to the scrutiny of a police investigation any more than Walt's last call to Skylar in Ozymandias was able to get her off the hook.
I know it seems like a feel good little piece of wrap up, but the evidence Gilligan provided us with just doesn't support it.