If you localize the stream (by downloading the music that would have streamed), you can mix all you want, even on the fly.
The really cheap way to do this is:
- Take a pen and paper, write down the names of the music/songs that play on your Pandora stream.
- Go to your local library, and find the music on CDs, and rip them to your computer/iPod. (You can also ask friends if they have copies of the music.)
- Put all the music you may want into one large folder, and familiarize yourself with it, so you can quickly mix on the fly.
- Enjoy the wedding.