Well, since it is a club house, you probably will have limited access and time that you can decorate. So here are some ideas,
1. cover furniture with white sheets (like is said before)
2. Dust table tops with baby powder for dust. Lay out mice, old books etc.
3. Lights - depending on what you have to work with
- High ceilings with spots/floresents and no dimmers - turn off and use candles (battery to prevent fires), if you can get your hands on some extension cords and some clamp lights (Lowes, Home Depot) use colored bulbs and position for the best effect. (if dimmers, turn down real low)
- Lamps - use cheese cloth over the shades and use colored bulbs (blue for the moon light effect, orange for that old house look)
- use blacklites where you feel you will be allowed to mount them (if at all).
4. Wall hangings - cover the edges of picture frames with cheese clothe and webbing.
5. Ceiling fans, hang cheese cloth, moss, bats and spiders. If you are going to have them on, keep the speed low and secure what you hang.
6. Floors - (I do this a lot to protect my carpets.) cover the carpets with plastic drop cloths, then you can throw fake leaves (or real if you don't mind cleaning the mess afterward) in the areas where you have any outdoor types of displays. If there is an area rug, consider covering it with an old rug or cloth to make it appear to be an old rug.
7. Ceilings - if you have a cross beam or a fixture (like a ceiling fan) that you can hang something from, set it up to drop down when a door opens, eye hooks, use dental floss as it slides easily and blends well with white ceilings.
8. Small decorations everywhere. Here is where the theme really comes into play. Do all Gothic, traditional, Victorian, etc. Since you probably have to be conservative on what you can do to the place...a theme will help pull it together. Example - windows: if Gothic - drape black cloth, traditional - use cheese cloth, Victorian - use more than one color, say black with burgundy ties, and some loops of burgundy material
9. Photo opp area - Guests like to take photos. Create an area near a blank wall that you can decorate or have a prop that guests will want to have their picture taken next to/in front of.