I have seen other members’ solution that seems to work ok and I copied it. The CRV is similar to the RAV4 and probably has a gap above the rear door of about 5 mm or so. A wide urethane or rubber boat roller is mounted on a plywood piece – a little longer than the roller so that the supports for the axle can be attached at either end. A small aluminum or steel angle piece hangs from bolts below the plywood to fit the door slot. All this is well padded with sticky foam or tape to avoid paint damage. The roller takes the sliding load of the boat as it is pushed up from the rear to meet the cradles on the rack. At some point, it pivots and the boat is up there. The rack need not have rollers, Hully or otherwise if the bars and cradles are well made for a bit of a fore and aft load. Once used, the roller is stored elsewhere. All this said, I don’t actually use this method for our double kayak which I transport hull-up (very awkward for loading but has several other advantages.)
Those proprietary side-loading systems may work, but seem way too expensive to me!
I’m happy to demo my (copied) device.