Hey there PEAS_PA welcome to the ROO owner family! My 2013 I have been storing the same since day 1 and it seems to work just fine with no issues so I'll share it in case it is along the lines of what you were looking for.
Passenger side forward comp. (under couch w/water heater on right side-front of trailer) I keep all my plastic leveling blocks, wheel chocks, hitch and weight distribution bars and acouple of pressure treated wooden blocks for just in case times. I installed a set of two fishing pole (plastic piece w/ open grooves filled with foam) racks inside on back of wood seat frame to hold all the metal slide and jack wrenches/handles. These stay in that rack cause I use a battery operated drill to set the stabilizer jacks...and that stays in this compartment as well. I store the vinyl/plastic camp mat that we lay on the ground outside our door by folding it up like it was in the bag we bought it in....and then I tuck it against the underside of the couch seat (cieling of the compartment) by using the false wall that separates the water heater as one side, and I use a length of 1x2 wood cut to sit on top of the wood rail under the couch and the top of the access door frame as the other side.
In the Rear comp. (left side of rig facing rear wall) I keep a hydraulic bottle jack, lug wrench, small tool kit, small rubber maid container (2.5 gall??) to hold septic tank fittings that I don't normally use but carry as "in case needed" a 1 gal rubbermaid drink style container I use for mixing toilet chemicals when needed, a bag/box of toilet chemical and the hose I use to do my black tank flushes. I also have a nice small plastic folding (from camp store) step stool I use for sitting while waiting on that flush to happen and tanks to dump.
In the Driver Side comp. under the dinette, I keep the grill, a Coleman camp stove, my power cord, my water hose and filter (small inline ones from walmart or camp store too) and I also have larger rubbermaid container (5 or 10 gal??) that I keep extension cords, awning lights, water pressure regulator, cable for tv hookup (although seldom used) and I also keep a collapsable extension pole with a 2ft window cleaning "t-bar" thingy that has the sponge like cloth on one side and rubber squeegee on other... I use that to clean/dry off my awning after camping before rolling it up.
PHEW...guess I carry ALOT of junk around in dem dare cabinets!
Ed & Chris
Josh & Jaclyn
2012 Suburban LTZ
2013 Rockwood Roo 233S