Mr. Dennis,
I think your idea is good. Model rocket guide rods are required to be three feet long. I doubt you would need that much length given how well the "carpet release" stooges work. Note that the smaller model rockets use 1/8" rod, and the heavier/bigger ones use 3/16" rod. Those models weigh significantly less.
Would you be doing this strictly for combat, profile scale, or FunFly/sport?
Taking a quick stroll through your idea, I can see a pair of guide tubes attached to the inboard side of a profile fuselage just in front/behind CG. Or a single guide tube attached to the inboard LE/TE, say on a combat plane. My concern would be abrasion of the wing/tube contact surface of the outboard sliding wing. I consider the rod easiest to see around rather than trying to monitor the whole shebang while watching around the PVC tube. It may be prudent to use a PVC pipe of large enough diameter so you could fit pipe insulation or a pool noodle over it.
Mr. Chuck, I "discovered" the drop off gear accidentally. The model was a gift from a gentleman in England. His build log is on RCG in the Control Line forum. When I fly from grass, I lay out four or five 2ft x 3ft pieces of overlapping rubber non-skid floor covering (the diamond textured 1/8" thick stuff). This stuff lays flat as it is heavy enough to matt the grass underneath...but back to the KK Radian. It arrived carefully packed with the gear removed. My first flight was made with the gear wedge inserted in the airframe. Before I made the first half-lap, it vibrated out. I was pleasantly surprised by the "performance change," so I never hard-mounted the gear in the model. I suspect the "socket" will wear out over time, so I do plan on securing it at some point.