Your TV boxes will work if you have a way of controlling the overspray. I'd suggest cutting open a couple trashcan liner or pick up a cheapy 1.00 shower curtain at the dollar store to go under your box and tape another over the top, Leave the top one open while you spray a coat, closing it when you see the overspray coming back out.
Your next step would be to devise so sort of venting system. A squirrel cage blower can be rugged up to a dryer vent hose run out a window or otherwise vented to the outside. I'm not sure if you can see the blower clearly in the photo of my small paint chamber but it's the black box on the back the silver hose vents the overspray and vapor out of the basement thur a coupling installed in my basement door.
Well what I planned on doing is :
Keeping the little ' flaps ' on the box so I can shut it again . Paint the rocket in side , shut the flaps and leave it ouside , but line the inside of the box with polostyrene to keep it warm. But puncture the top of the box to realease the gasses.
No need to puncture the top as a matter of fact if your going to leave our box outside you may want to cover the entire box the plastic to keep rain and dew from damaging the box and model inside. If you really think you need to vent do smile slits about 2 inches for the top folded out for the inside forming a vent shield.
Don't forget to convert a wide base lazy susan to mount your model on make a world of difference for easy handling.
I thought about building a booth out of one of those great big Rubbermaid trunks and using my shop-vac wih a hose on the exhaust to leading to a window to do the venting. Other than lack of motivation, my only concern was the possibility that the airflow would be too fast.