We've found the easiest way to figure out where we're going is to simply get some basic AAA highway maps and then sit down with people in an area and ask them for the best route - they have always been more than happy to help us out.
We haven't used Google maps at all, but then we are notoriously bad at planning our route and like to leave it open til the last minute. If you like to plan things out in advance, it is probably a great tool.
As for the ACA maps - they are a mixed bag. Yes, they are great maps and have tons of wonderful info on them. They tell you everything you need to know. That's the problem with them too. In many ways, they tend to take the unexpected out of touring - and that's what we like best.
We've also found that it's harder to meet local people when we jump on to an ACA route for a while. It's like there are so many cyclists we just get jumbled up with all the rest and nobody really notices us or takes the time to talk with us. When we're not on the ACA route, we meet tons of people and that's one of hte best parts of touring for us. For that reason, we tend to stay away from the ACA routes.