Downloading mytopo maps

So I read the thread about how to download maps for an entire state.  I am trying to download for the lower 1/4 of Arizona.  I have selected the appropriate area and began the download.... After about 40 hours of downloading, its at "52% of 79858."  Its not hung; it still chugs along, albeit slowly.  I am on wifi but I am wondering if the download is happening on Verizon's 3G network, and if they're throttling me.

Any ideas?