loonwheeler
Adventurer
Assuming the U1600 and U1750 models are stock, I would imagine the U1750 would be the better choice IMHO. Longer wheelbase (3250 mm vs 2650 mm) and with the stock turbo engine @ ~170 bhp provides a nice amount of power for this type of application. While the 1750 is a bit heavier, it does have a higher payload capacity which can come in handy especially with providing enough gear, food, water, etc for more than 2 people (4 kids in your case).
How long / wide is the camper body in the last photo?
How long / wide is the camper body in the last photo?