KERA has a great story on the progress in connecting Fort Worth's Trinity Trails to downtown Dallas with trails along the Trinity River making a 64 mile bike superhighway.
The story says that there is hope to get the cities connected within 4 years.
Here's a map of the proposed routes:
And here's the story at KERA.
And here's the North Central Texas Council of Governments "Regional Veloweb" info.