If you are coming to the downtown Johnson City areas from the east, I have one word for you: Tweetsie. The Tweetsie Trail is a fantastic rails-to-trails project that connects Johnson City to Elizabethton. The JC side of the trail is especially great since there are no intersections with roads with heavy traffic. Elizabethton, however, has quite a few trail crossing on busy roads.
If the Tweetsie has no good access points for you, there are other alternative routes to consider. Although it might be worth looking at where the closest access point for you is, since it is some of the only automobile-prohibited bicycle infrastructure in Johnson City.
The Tweetsie Trail
The Tweetsie has to be my favorite trail in the whole city. While I love taking my bike out to Tannery Knobs and Winged Deer for some fun, the Tweetsie is the only trail that I can use for both transportation and recreation purposes. There are even plans currently to expand the Tweetsie on both ends, east toward Hampton and west toward Jonesboro! When finished, this will allow bikes and pedestrians to travel even further on safe, meaningful infrastructure.
Follow the directions under the Keystone category for more information on how to safely get from the Tweetsie Trail trailhead in Johnson City to downtown. The trailhead is near the corner of Legion and Alabama Street.
Key Stone Area
If you are near Key Stone, staying on calm neighborhood roads is a good idea. Orleans Street has no big, steep hills and remains fairly low traffic. The only tricky part is crossing over Legion Street at the end of Orleans. There is no traffic signal to help you unless you go all the way up to E Main Street. If you choose to cross at Orleans, be aware that cars coming from Milligan Highway speed around the bend all the time.
Once you have crossed over Legion, there is a gravel path alongside the street that bicycles are free to use. It can cause trouble with steering and pwer, so make dure you feel confident enough in your bicycle skills before taking this path.
Maple Street is a calm-ish road that connects to the rest of the Tree Streets, making a much safer route than traveling along State of Franklin.