Ok that kinda sounds like the common purpose doctrine .The simple answer is ask the people operating in Alaska.
I know someone with a fishing lodge. I believe flying in is 135. Back and forth fishing day to day is not. If you just fly a friend in for fun, 91.
One thing to remember is you are dealing with federal law direct. Not federal law distilled through a state. You,to the FAA, is the same as Boeing, American Airlines, SpaceX, private pilot or one with every single license; all are responsible the same amount if you play in the sandbox. You are responsible for the rules you can’t use just to know you can’t use them. There is no poor little ole me with the FAA. They will throw a million dollars at you to keep you and your little $20,000 airplane on the ground. The FAA is always swinging an ax, some days it’s sharp and it’s a clean kill; others it’s dull and they bludgeon you to death. Mistakes are made and usually fixable, but never stick your neck out. It’s not the persons that work for the FAA, it’s how the rules are set. There is more than one reason most of the staff is retired military; a big one is they will follow orders without question.
Thread drift - IIRC Little Audrey’s fuselage was originally in the Howard ‘Pete’ racer of the 1930s and when LA was restored a new replacement fuselage was made so that Pete’s fuselage could have a new everything else made for it too.Paul Poberezny built "Little Audrey" with shorten Luscombe wings and a cut down T-Craft steel tube fuselage.