I would question anyone who doesn't know the Silver Comet starts on the NW side of town.
Here's the first paragraph from the Silver Comet Website:
Silver Comet Trail Georgia - Welcome 
"The Silver Comet Trail is located 13 miles northwest of Atlanta, Georgia. It's free of charge, and travels west through Cobb, Paulding, and Polk counties. This quiet, non-motorized, paved trail is for walkers, hikers, bicyclists, rollerbladers, horses, dog walkers, and is wheelchair accessible."
Anyone who lives in Atlanta knows the 4th Ward & Memorial Drive/I20 corridor is dangerous. Just a few years ago, Atlanta started bulldozing the vacant buildings down there to try to drive out the scum. We all know Grant Park is dangerous. Heck, I have a lady friend who lived down there and her house was broken into multiple times a year. They sold the house at a loss because no one would buy it in that cesspool part of town. It's one of those areas where one street will have nicer homes & the next street will be half vacant shells & crack houses.
Just go check out any crime mapping website that will show different types of crime. Ignore silly stuff like theft. Just search for murder, assault & ****.
Decatur looks golden. Anything near or South of I20 is crap. It's actually worse on the West side of town.
As for your route... The challenge is getting across I-20. Obviously, there are a limited number of places you can do that. If it were me, I'd be interested in staying safe. That would mean riding where there are plenty of people & avoiding residential side streets. The obvious choice in that respect is Moreland Ave to Glenwood. Moreland is a pretty busy road, though.