The tip about Keystone is correct, that can be a pretty busy road with no shoulder, but you won't be on that road too long. If you don't want to ride on SR54 (six lanes with shoulder) you can take Little Road north of SR54 to River Crossing, then right to Starkey Road, left two blocks to the entry to Starkey Park. Inside the park is the Starkey Park trail, 6.5 miles of a nice trail that ends at the Suncoast trail about 4.5 miles north of the SR54 crossing. That is the way I would go as the traffic can be heavy and fast on SR54.
Sounds like a great trip!