Here's demographic information from RV Life Magazine as of April 2013:

Age:

11%  30’s – 40’s    
71%  50’s – 60’s    
18%  70’s and older    

Gender:
76%  Male    
24%  Female    

Marital Status:
89%  Married/Partnered   
11%  Single    

Annual Household Income:
28%  Less than $50,000    
51%  $50,000-$100,000    
15%  $100,000-$150,000    
  6%  Over $150,000    

Type of RV Owned:
53%  Motorized            
47%  Non-Motorized    

Years Spent RVing:
27%  Less than 5 years    
41%  5-20 years    
25%  20-40 years    
  7%  Over 30 years    

Weeks Spent RVing Annually:
  9%  Less than 2 weeks    
28%  2-4 weeks    
23%  4-8 weeks    
19%  8-12 weeks    
13%  More than 12 weeks    
  8%  Full-timer    

Weeks Spent Traveling Outside of an RV Annually:
44%  Less than 2 weeks    
40%  2-4 weeks    
16%  More than 4 weeks    

Favorite Activities When Traveling:
93%  Sightseeing    
74%  Scenic Byways    
67%  Local Events & Festivals    
60%  Outdoors/Hiking/Walking    
48%  Dining Out    
43%  Fishing    
36%  Shopping    
33%  Wineries    
31%  Casinos    
28%  Bicycling    
22%  Boating    
19%  Golfing    
  7%  Motorcyling/ATVing    
  8%  Geocaching    
Other: Museums, Microbreweries, Hunting, Dog Shows, 4-Wheeling, Antiques, Photography, Dancing, Socializing, Prospecting, Birding, Meeting Other RVers, Seeing New Places, Visiting Family, Cruising, Boondocking, Archery, Whitewater Rafting, Historical Sites, Adventuring, and Steam Trains

What Toys You Own:
90%  Computer/Laptop    
71%  GPS Device    
63%  Bicycles    
57%  Tow Vehicle    
52%  Fishing/Hunting Equipment    
51%  Smart Phones    
31%  Boats/Kayaks/Canoes    
29%  Golf Clubs    
27%  Motorcycles/ATVs    
19%  Metal Detectors    
Other:  Digital Camera, iPad, Tablet, Ham Radio, Guns, Summer Home, and Airplane