Thanks.
Here's what I did so far, with your help, with the hope it'll help someone else.
1) http://mt.google.com/mt?n=404&v=w2.99&x=%d&y=%d&zoom=%d
needs to go into Maps -> Manage Repositories -> URI Format.
2) Into Maps -> Manage Repositories -> Cache Dir, in my case it's /media/mmc1/Maps
3) Now a map of the world appears.
4) Use the rocker arm (+/-) on the top of the 770 to zoom in. Zero in on the area you want, in my case New Mexico. Change Maps -> Manage Maps -> Zoom from 15 to 13. Turn on Autodownload. Center on Albuquerque. Let maps download. As above, change zoom level from 13 to 11. Keep centering and changing zoom level, using the stylus or the arrows to the left of the display, until you have the area you want detail of.

Is that correct so far?

p.s. Still can't delete from the program.