The Vlad them could work, because the wars, impalings, etc. were all "outdoor activities". Haunted trails have the challenge that they (usually) need to be things that would naturally be outside.
But make sure that you create something to block the views from one scene to the next. Otherwise there is no suspence. You can cut and move foliage to create these barriers, or sometimes you can hang black plastic from trees, poles, lines, etc. Just make sure there's a way to block so people can only see one at a time. Also, the guests perceives it as longer when there are twists and turns along the way.
It is also good to throw in a few changeups. I like to add humor occasionally, which often takes them off their guard enough for a really good scare. Don't just focus on gore; young guys enjoy it, but it does very little for anyone else. You are trying to entertain, and that keeps them coming back for more.
Take a good look at your resources (props, electronics, actors, makeup) and then come up with a story line, whether it is the Vlad theme or something else. A coherent story is critical, as it helps to "suspend disbelief" as the Leonard Pickel has often said. You need to have something that gets them caught up in the scenes and the images--especially the ones they create in their own mind, which are much more effective than anything you will create physically for your guests.
So take a look at resources, create a comprehensive story, throw in a few changeups, and create barriers that will force them to see only one at a time, and dread what might be coming next.
When creating a theme, take advantage of location, etc. Could this be a good location for an archeological dig, where some funky burial was discovered while preping for a housing division? Is this a good spot for an interrupted Halloween ritual? Maybe your neighbors had been complaining about strange sounds when the moon is full. Toxic waste can be a lot of fun, and I think it resonates where I live by a nuclear facility. When theming it helps to look at what is around you, and take advantage of the "set" that you did not even have to build.
Good luck! I hope this was a tiny bit of help.