Rick,
As anybody that knows me also knows that "Navigator" has been my job title a lot of my life, I get asked about this a lot.
The short answer to your question is YES.....
Standalone GPS are great for knowing where you are and what you have to do next, but for planning, they suck.
The navigator packages (Strips & Treets, Street Alas and Coopilot) are great for planing the route, but are pretty much useless to the driver on the road as they can't be in front of him and aren't very good at knowing where attractions are.
That is why you need to start with the online things like AAA, Google and Roadtripper, but even they can't find everything. So, work all the online resources you can find and make lists and plan all you can before departure.
I usually have to stop my planning effort when it is time to put the laptop in the coach. It actually doesn't stop then, but when DW is driving, I am using the phone to get internet and watching progress on SA (outgrew S&T years ago) and even modifying the plan on the fly.
Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.