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I would have to imagine that your son isn't much help with loading and unloading and towing of the two man being only 6 years old. Why not use the two man setup that you already have and put the money towards ramps to load and unload into your vehicle.
bought a glidelite to train myself to travel light. 4 rods. bucket to double as seat and bait bucket. flasher. 2 plano plastic boxes for tackle. 4 tipups. thermos, maybe a sandwich and snacks. bait pucks in my pockets. extra pr of gloves
I love my glidelite after some mods to attach my LX-7 head and GPS mount. However, there are days when the shanty is a more comfortable option. Having both is quite nice.