Don't have any facts, just anecdotes :D
Massanutten VA built an indoor waterpark about a mile from the slopes about ten years ago. It does really good business with the casual, southerners that frequent that mtn. Good as in daily, large apres ski crowds. It's a big draw for families.
In 2005 I took a ski trip to The Homestead, VA. It's a resort that operates a 700' vertical ski area in winter. It's similar to the Mt Washington Hotel . In fact both hotels are Omni resorts. The Homestead is more known for summer golf, but has dining, shops, tubing, skating, horseback riding, etc in a huge, old resort complex. We were there over President's Weekend, yet at one point a gentleman, with family in tow, saw my daughter wearing ski clothes in the elevator and remarked, “they have skiing here?” The ski area represented a smaller, added attraction.