I have been experimenting with various films. Monocoat which is used mostly in the RC aircraft world for skin of wings and such adheres to cardboard and plastic really well and add sheer strength too. Monocoat comes in a whole bunch of colors and runs about 15 bucks a roll. One roll is enough to cover a lot of mid power rockets. Self adhesive films are also fairly easy to work with and give good finish results. I have built a number of boost rockets and boost gliders and use the shiny chrome on the bottoms of the wings with very little weight gain. $3 bucks for a 6x36" strip. I've attached an example of the results. The fins, couplers, upper airframe and nose cone were covered with film.

Rangertech in Forks, WA