Cutting and building a paper model is a great activity that you can do with the kids. There are a lot of free patterns on the Web. You may wish to stop first at a printer for a better printing job on cardboard. Keep an extra copy in case you ruin a piece while building your haunted house paper model.
You can stop at assembling the model. But you will get a bigger Wow factor if you do a few extra steps. Look at the impressive carving job of Ray Keim. He added moss to key places on did his Skoolhouse. For the piece de resistance, Ray carved several Potka Pods as decorative pumpkins. You do not have to carve them. Simply, putting a few Potka Pods will elevate the results. You could also deposit on the floor small pieces of hay and hang spider webs.
Ray Keim produced many paper models. His latest addition is the Bates House Paper Model. Visit Haunted Dimensions for downloading the kits and getting inspirations on how Ray and other people have decorated their paper models.
Cute but simpler
Another model that I like is the Haunted Church with cemetery by Paper Models. This one is for sale. They give you the choice of downloading their model or opting for a printed kit that they will ship to you. The Printed Kit is available in 3 dimensions.