I would go with the Lance 1010 which was an excellent design. I would question how much you will actually use the shower in a camper. We never use ours and prefer the campground showers or go without. Even friends with 5th wheel trailers prefer to use the campground showers.
I would focus on the capacity of the holding tanks, the size of the fridge, cabinet space for holding food and cooking items, space for clothes and personal gear, space for a second battery, and similar functional aspects of the campers you are considering.
I would not bother with a dually as they are only good if you have a 4500 lb. load and don't mind the crappy turning radius and extra 2 feet of width and parking problems, problems with using tire chains, cost for two more tires. Under 4,000 lbs. and a SRW can handle the load with the right tires and over 4,000 lbs. you still have the option of 19.5 rims and tires.
The Lance 1010 has a published dry weight of 2690 lbs. which means the one you may be buying probably weighs around 3,000 lbs. and with gear will have a weight of 3500 lbs. which your truck can handle with some mods.
My Lance 845 when ready for a trip has a total weight of 3400 lbs. and my 3/4 ton truck handles it with ease. I did add Supersprings and I did replace the factory tires rated 3195@80 PSI with Nitto tires rated at 3750@80PSI to have more than enough load capacity.
With almost any truck you will need to budget for tie-downs and turnbuckles and additions for the factory leaf packs and shocks and higher load rated tires. Often a rear anti-sway bar is needed, particularly with the Ford trucks.
CAT scales are invaluable and well worth the $10 cost to have your truck weighed before you add the camper and with the camper loaded in the bed and with the camper loaded with gear and provisions for a trip. Then you know exactly what the load capacity should be.