The goal is to add the HostGator server to be an exact mirror of the domain, then to add that server as a 2nd A record to my DNS zone. That way half the visitors to the size will be taking up resources and bandwidth on the HostGator server instead of mine.

Round Robin A records in DNS are intended to evenly distribute queries between each host of the same name. Using some tricks straight out of a hackers toolbox we can verify if the distribution is taking place. (It is.)