I've used the trick of putting Vaseline on the cut parts to keep the moisture in, seemed to work a little bit as in the pumpkin lasted a couple extra days maybe.
I also tried once and it worked, soaking the pumpkin in water for a good 4-6 hours. It was starting to shrivel up so the day before Halloween I filled a utility sink with water and put the pumpkin in and submerged it and it absorbed water and looked great again. It was only good for Halloween day though and then Nov. 1 started shriveling up again.
I can build a static prop very well but I kind of such at motors. How do I wire up a wiper motor and hook it up to make a seesaw go up and down? My plan is to make a haunted playground addition to my graveyard this year.