Hey Jacob,
Have you been taking lessons? Maybe a little background on your dance experience will give us some point of reference, but in the meantime, I can tell you that the type of waltz that would be appropriate is Viennese Waltz.
Instead of a box step, basic Viennese Waltz is done with balances. You should consult a dance teacher in-person with your music if you really want the right help.
Another key to dancing to music that seems fast to you is to take smaller steps. Smaller steps will make you work less and you'll look like you're enjoying yourself instead of running a marathon.
Also, another thing you can do is get the music pitched/slowed down, so that it's more do-able. You can see a deejay in advance that can do this for you, or you can find some tools to do this on your computer.
Good luck, and most of all, remember to have fun and smile (that's worth a lot more than the steps you do during your wedding dance).
--Porfirio
"Do or do not, there is no try," Yoda, Episode V