This is just the main loops in Simpsonwood. If you include the 2 other loops that you can only see once you’re on the trail you can make it closer to 4 miles per loop. It’s really nice, secluded woods and goes by the river as well. It’s a great place to get away:
http://www.mapmyrun.com/run/united-states/ga/norcross/208341532
This is the Peachtree Corners area as well as Berkeley Lake which has a ton of really wide sidewalks and in general is pretty good to run in, especially on the weekends:
http://www.mapmyrun.com/route/us/ga/norcross/342624475505
This is just the Berkeley Lake loop if you wanted a good road based loop to do some miles on. It’s in a neighborhood so traffic is low and it’s got reason
http://www.mapmyrun.com/route/us/ga/duluth/735630345105
You can also include Ridge Rd to N. Berkeley Lake Rd if you want a variant.