After I posted my first post (ever, on this forum) with that question, I called the Millenicom guys, who told me that peripherals like a printer or net drive DO work but they count against your monthly quota. He recommended getting a 3G router, specifically a Cradlepoint MBR95, to handle the within-LAN traffic, and anything that goes outside the LAN uses the monthly quota. That way I get to watch stored movies, family pictures, etc. from the hard drive without dinging the quota. Probably the way I'll go when it's time.