Question on the UPS integration-are we able to print shipping labels right out of Netsuite?

Yes, NetSuite integrates with UPS via API to create a shipping label. Then print within NetSuite to create a pdf/zpl/epl file to print depending on your label printer.

@Nick W. Do you know if UPS offers the option to suggest box size based on the size and weight of the item?

It does not do any type of box size recommendations. You can set the default box size and add a list of standard boxes for a drop down list. Or manually entry if not standard.