[Answered ]-Is there a less-database-intensive way to get data from my extended Django Site model?

Since you subclassed Site you should be able to just do SiteMethods.objects.get_current(), which will net you an instance of SiteMethods. Since Django’s implementation of MTI (Multiple Table Inheritance) uses a OneToOneField to the parent class, you should also be able to use select_related for site. So, try the following:

SiteMethods.objects.select_related('site').get_current()