We live in Northern Minnesota and have been to Itasca State Park many times.
It is a beautiful park, and has two campgrounds. We prefer Pine Ridge campground, which is away from Lake Itasca but has a more wooded atmosphere. Bear Paw campground is right on the lake but more open. Lots to do there. The Douglas Lodge was built by the CCCs and has great meals. They have two excellent visitor centers. The one by the East entrance is far more educational than the one at the headwaters outflow. Be sure to take Coborn's Boat tour to learn about the history and exploration of the area, as well as see some interesting wildlife (eagles are almost always seen on the boat tour).
We took the Great River road up from Kentucky back to Minnesota last November. Very beautiful views for much of the route. There are many state and other parks along the route for camping. In many places, the byway runs on both sides of the river. We used this to try to avoid the big cities when we could, but perhaps you want to explore the cities as they have a lot to offer as well.
I also just finished reading the book "One Good Story" by Ron Severs. It is a quick read, but he travelled from Lake Itasca to the Gulf of Mexico in a kayak a few years ago, camping along the way with just what he carried on his kayak. His overall takeaway was that the people he met along the way were the absolute best part of his trip. It might be fun for you to read this or take it along with you to read on your journey. Here's the Amazon link:
"Link to One Good Story by Ron Severs"And here is a link to the National Scenic Byways website. There you can get email contact information for each state that has the Great River Road running through it and they can provide more specific info for that state. I used to work for the National Scenic Byway National Resource Center and we could have provided you with all this information. However, US-DOT chose to defund pretty much the entire program about 4 years ago. So there is little support for existing National Scenic Byways, other than the local byway organizations that promote and manage the byways and many are struggling. When accessing the National Scenic Byways link, be sure to click on the individual state maps and photos link on the left side of the page. Lots of detailed maps and great photos there.
Link to Great River Road info, individual state maps and photosAnd here is a copy of the final edition of the Journal for America's Byways. While geared toward managers of scenic byways, it (and its two other companion editions) can give you an idea of some of the byways you may encounter along your route and in other areas. There is an article that deals with the Mississippi River byway in Minnesota, and one that highlights the Creole Nature Trail (In Louisiana, but not on the Mississippi River).
Byways Journal Issue 3 - Mississippi River Byway and Creole Nature TrailByways Journal Issue 1 - Roads designed for Pleasure, Part 1Byways Journal Issue 2 - Roads Designed for Pleasure, Part 2