I had the same issues the first time i went through and downloaded the tiles for the AT one-at-a-time.

A much better, and in my opinion easier, way to download map tiles is by selecting the "rectangles" point type (under "view") and then clicking: Point->Download maps. From there it lets you determine what level of detail you would like. Every tile contained in or touching the rectangles is downloaded in the specified quality, and the perifery is also downloaded in lower-resolution (probably because further zoomed tiles cover a larger area).

I'm having a much better time downloading maps using this method.

Good luck and safe travels!
Eli