I crated and shipped a game once and I will never do it again. The only games it is worthwhile to do it for are the really rare high dollar games (read as vectors from anyone besides Atari and anything laserdisc besides Space Ace and Dragon's Lair). Anything else can be bought or sold locally. Any popular classic can almost always be found within driving distance (really they can, the popular games are VERY common). Those same popular games are also just as easy to sell locally.
Any unpopular classic games are not worth the sheer amount of labor involved in crating and shipping them (and no conversion games or post '83 games are worth shipping). Really after doing it once, I can say I would have rather sold locally for $100 less.
Basically the "average cab" is not worth the hassle of shipping. Especially between 2 far flung hot spots anyway. (Florida and California both have tons and tons of games, if you can't find a buyer or seller for the game you want in those two states, then you are not looking hard enough).
But if you must crate and ship, then go with forward air. They are who I used when I did it. They were friendly and the game got there fast. You have to call the local office to get a quote though.