I'm planning on some training hikes to prepare for the Appalachian Trail.  Any suggestions on where to start?
Hiking is fun! Doing some preseason training can be a big help. Make a work out plan is designed to target areas that power you up the trail mile after mile.
I was even thinking off doing some mid-range overnight hikes just to get used to the flow of hiking all day, then camping at night.  
That's exciting! Over night hiking offers a different perspective of the scenery, relief from summertime heat and a deep connection with the outdoors.
Good points.  Do you think May would be the appropriate time to start the training?
This depends on many things. Where do plan to train? How long do you plan on training for. When would you like to attempt the Appalachian Trail?