I would be concerned that it is terribly overweight. Vibe and Matrix were build on Corolla platforms. To the Pontiac naysayers, I own a 09 Vibe, no problem getting parts, go to any GM dealer and order or order online on the many GM dealers selling online. Any chassis related parts can be gotten at a Toyota dealer, they stock quite a bit as the platform is shared by a Corolla.
Years ago, dedicated camping stores (like Campmor in NJ) used to sell 1 lb propane bottles specifically made to be refilled. It has a small bleeder screw on the top in place of the Schrader type valve. I have a couple of them and still use them occasionally. I got a 4lb Worthington tank for my Baby Q one time when Camping World had them on sale. I can go all summer with one fill and much more convenient.