Even with a co-pilot, I like to know what is in the general area that we'll be traveling before we leave. The last time we did this, neither of us had a smartphone and our laptop died after the first night of the trip. We took I-10 from its start in Jacksonville, FL to Houston, TX, so I checked out all the campgrounds around were we'd be likely to stop each night. I plugged them into Streets and Trips and saved each day on the laptop.
Like I said, the laptop died after the first night, but I had enough familiarity from setting those maps up, that I had a general idea of where we could stop when we got tired of traveling. We didn't have any reservations except for our destination. We found a few really nice campgrounds along the way and had a great trip.
-Michael