Tongfamily.com

Adventure Cycling Association. They have a really detailed set of maps that go from Vancouver BC to the LA area. Just $47 if you are non-member, $33 if you are a member of Adventure Cycling Association.

Also, they have GPS information you can load directly into a Garmin GPS unit or if you have Magellan, you can use a third party tools called Oziexplorer that also lets you load third party maps. These are way cheaper than buying mapping information from Garmin or Magellan (although who knows how accurate). I’ve already spent for example $300 for a Magellan GPS and then $300 for various maps, so this is a real savings.