Here is a little math for your consideration.
Lance 950S dry weight is approximately 3100#. Wet weight will be 3500#. Does that include any accessories such as awnings, upgraded mattress, microwave/oven, solar panels, upgraded battery, etc? Let's hope so because those items can add a lot to the base spec weight. Anyway what weight is reasonable for your and the passengers? 400#? That will bring the weight to 3500#.
The rule of thumb is to add 1000# for "personal" items. That sounds like a lot but in my experience it has been hard to keep under that amount. This category includes such items as chairs, bbq grill, generator and fuel, tools, clothing, sheets/bedding, towels, cameras/electronics/hobby gear, extension cords, leveling blocks, cleaning supplies, black tank chemicals, etc, etc, etc. Let's not forget kitchen gear, plates, pots and pans, flatware, etc. Another big item is food and drink. Lug in your weekly groceries and you will quickly realize food and drink can get really heavy.
If you start with a camper in the 3000# range, you will very likely exceed your 4400# capacity. Some suspensions mods will be needed. Depending on the State/Provence being over the limit can be a legal issue. Another issue is weight distribution. Except for passengers, almost all of the cargo weight will be on the back axle and tires. Depending on wheels and tires, you will likely be at or exceed the maximum load specs.
You want to be able to use the truck as a second vehicle so avoiding a dually makes sense. You might want to reconsider. That supercrew and 8' bed are already issues for daily use. The length alone will make it difficult and sometimes impossible to maneuver in and out of parking lots.
