Your not confusing the propane store compartment under the loft with a common storage area are you? There is not much room there unless you go to smaller bottles or remove one. The two small front/side compartments will hold you blocks, chocks, cord sets, hoses, trailer power cord, and small items. Chairs, grills, gen sets, coolers, DO's, and outdoor carpets will need to ride low in the truck bed around the 5er hitch. I hope that answers your question.
There is a rear storage access on the curb side. It is basically in the curb side of the u- shaped dinette bench. This rest of the area is where the batteries, power converter, hot water heater, and the water pump is located. I keep some accessories and small camping items in this storage. Plus the awning and stabilizer cranks. Storage items are limited by the size of the door.
The freshwater tank is strapped to the frame underneath.
Great!. I thought the propane tanks went there but I wasn't sure just how much room was available. The front box on the 19 is just plain convenient and I am trying to mentally replace it in the 5.0. The extra step/shelf idea is also very clever. Thanks for the pix.