A hybrid, such as the first picture, would probably be a reasonable choice for weekend use. You can decide to stay home if the weather isn't likely to be cooperative. Hybrids and pop-ups are not fun to set up or take down in wind, rain, cold, or any combination thereof. Also, the bed is usually exposed to the elements during setup/takedown. My suggestion would be that you consider the trailer potty room as something to be used during the middle of the night or bad weather, when you don't want to trek to the campground shower house.
You might also want to look at a rPod, such as this one: http://www.forestriverinc.com/product-details.aspx?LineID=173&Image=5054&ShowParent=1&ModelID=971#Main
for another idea. Something to think about: can any of your children, either singly or together, figure out how to escape from the trailer? That's one disadvantage of a hybrid.