Your main issue with a Lance 910 is not weight or CG. A well maintained F250 can easily handle well over 3000lbs of payload in the bed without putting anyone or anything at risk. They generally weigh about 2800lbs empty and have a 6084lb rear axle weight rating with stock tires. Newer ones may actually have a higher weight rating.
Now someone will pipe up and say the axle is rated to 10,000. Well the AXLE is, but the SUSPENSION SYSTEM from the tires to the rims to the axle to the springs to the frame to all the rivets and fasteners holding it together is rated to 6084. If you put 5000lb each rated tires and rims on the axle, and jammed a section of well casing between the axle and frame, sure, you could probably run 10,000. Off the showroom floor, not so much.
Back to the point. Everything I'm finding on the lance 910 is showing that it is a long bed camper. Putting a long bed camper on a short bed truck leaves 18" of floor hanging off in open air that was designed to be supported by the truck bed. Maybe it will work okay. Maybe the camper isn't strong enough. You're not going to get anybody to give you a definitive answer one way or the other. Lance's official line will be "Long bed trucks only" because they are liable if they tell you to go ahead and the camper falls apart. From there you have to decide to listen to the Internet experts telling you to go ahead it will be fine, and decide if the risk is worth the reward.