Ok. The problem can't be my ISP. I switched to OpenDNS's servers and got an immediate speed increase and reliable service for about 5 minutes. then I tried to open Amazon.com and it's just spinning it's wheels. Weirdly enough, I can continue to surf on other sites that are already open, but Amazon won't resolve. I'm sure the request is either not getting to OpenDNS or that it's not returning. Page refreshes don't seem to make a difference.

The modem continues to work fine when plugged in directly.

Problem has to be the Cradlepoint router. I wonder what could cause it to randomly stop loading some sites and not others?