Hopefully while the Southeast Connector Project is underway TX DOT will also continue upgrading US-287 between I-20 and I-45 up to Interstate standards.
US-287 is a freeway from I-20 down through Mansfield, just short of the TX-360 interchange. From there it's a mix of brief freeway segments in Midlothian, Waxahachie bracketed by segments of 4-lane road with driveways and at-grade intersections. The whole thing really needs to be 100% limited access freeway only.
I think the US-287 upgrade project in Ennis is pretty much finished, save for the fact they need to overhaul at least one or more interchange ramps at I-45. The SB US-287 to NB I-45 cloverleaf ramp is a tight 35mph rated loop. Another short freeway upgrade project just East of Midlothian is in progress. However, the way those plans looked there will still be at least 2 or 3 at grade intersections between the Midlothian freeway segment and this new one.