The average of 3300/year driving is a tad low as 5000/yr is recommended but if it was given regular maintenance and appropriate time based road trips that shouldn't be a problem. An engine/tranni/drivetrain should be exercised on a regular basis. Out on the road, not on a parking pad. Since you already bought it, you probably have the maintenance records so peruse them, they'll tell you whether or not you need to get right on changing stuff, or can hold off a while.
Newmar is generally considered a high quality rig, and at only 40,000 miles, hope you got a gem.
Good luck and happy miles!