I live in the area and agree with above. West side of Ft Worth stay on I-20 at the I-30 split. Goes around the south side of both Ft Worth and Dallas. Then I-635 up the east side of Dallas to I-30. And mid day. Normal traffic flow outside of rush hours runs at speed limit or above. Unless there is an accident or construction. But other than getting off on secondary highways there is no other way to get around the DFW area.
I would personally suffer thru a little traffic backup on I-20 than take I-30 thru downtown Ft Worth and downtown Dallas. But looking at google maps traffic for potential traffic problems is a good idea and may let you decide to stop for lunch or rest break to let it clear.