Indeed I have! I took a ride on an Era DC-3 about three years ago.
Era completely gets into the retro thing...flight attendants wear 1940s styled air hostess outfits, original leather seats, Life magazines and Glenn Miller playing in the departure lounge. All of it is very stylish.
Airline personnel give passengers plenty of opportunity to walk around the airplane, take photos, snoop around the cabin and cockpit.
The aircraft that we flew on appeared to be in tip-top shape and it had beautiful markings. Red and white paint on a polished silver fuselage.
The only thing that I will caution you about is your flight to Denali (Mt. McKinley). There are very few days in the year when the peak is not obscured by cloud cover and, since Gooney Birds are not pressurized and rarely exceed 10,000 feet (Denali, I believe is about 20,000 ft), you won't go very close to the mountains unless you have a particularly clear day.
We were fortunate. The clouds cleared about the time we took off and we had some truly spectacular views of the mountain range. We actually threaded through the peaks, due to our limited altitude. It was a breath-taking experience.
Also, cabin service was lots of fun: champagne and cheese.
I trust you will enjoy your trip.