A wealth of information jefnvk, thanks. That's what I was looking for. Sounds like the Northern "bridge" area roads will be fine on the mountain bike. I'll ride whatever works. Its the being out that I enjoy. I had heard of the Meijer Heartwick and Pere Marquette trails and have them on my list. Thanks
CliffordK, I looked at the Katy Trail and since its crushed limestone, I'd use the mountain bike. Sounds like a great trail and it connects to the ever-expanding Rock Island Spur for a few more hours of riding. A little distance from here (571Google miles), but you never know. That List of Cycleways is quite the long distance bikers dream isn't it. Michigan to Washington State for one example. Reminds me of an old Ranger friend of mine, Doc Giblen, who rode from the coast of Washington State to the Eastern Coast. Always thought that was quite the accomplishment but we were 40 years younger then.
To bobwysiwyg, the Kal-Haven trail looks good for the mountain bike and isn't that far from the GR trail. It's nice taking both bikes. It allows me to fit the trails.
Thanks all.