Question On Configuring Shipping

Hi everyone,

This is my first time posting. I am setting up our Multi-vendor store and want to start with just having users specify a flat amount for shipping costs. With some help, I've managed to make that happen. However, I am curious how people have gone about setting up for the "real time" methods.

For example, did you just go and get a list of all states and create a zone for each? Or do certain methods require more specific data, such as zip codes? Do the freight carriers such as UPS, FedEx, DHL, etc, typically offer this information on their sites in a format that is easily uploaded to CS-Cart?

Thank you!