Your great grand father's information can be verified using the Civil War Soldiers and Sailors System, http://www.itd.nps.gov/cwss/index.html. He's the only Enoch Howe I found and was apparently in both E and I company of the 8th Michigan Cavalry throughout his time in the service. The personal information provided by the site is essentially the bare minimum from his service records, but if you click on the unit history you get a run down of the movements of the 8th Michigan Cavalry, their battles and where they finally muster out, which is Nashville, TN.

It's important to note that while your relative may be mustered into service in Kalamazoo, the 8th is listed as mustering in at Mt. Clemens. This is most likely due to the fact that the regiment as a whole mustered into Federal service in Mt. Clemens, where the individual troopers mustered in where ever their companies were from, in your relatives case, Kalamazoo.

Hope this helps!

Matt Borders