For now it will be strapped down, unable to expand. Thinking of bolting the sub frame to the bed in the future, would secure it to the truck and allow for the sides to be opened.
I can't expand the sides at the moment anyways, my bed sides are in the way.
What's fuel economy? Haha I don't know how much the camper will reduce the fuel economy, this is the first time its been on the bed. I averaged 10mpg without the camper cruising at 55-58mph, trailer made no difference. The camper makes for about 4 feet of a vertical wall over the cab to catch the wind.