ditto to stopping for a quick visit to Judge Roy Bean Museum.
Sanderson is about 90 miles from Del Rio...good for refueling if needed.
Stay on 90 all the way to Van Horn.
Marathon has a restored old hotel with gourmet dining if you like that. Can't miss it. The Gage Hotel if you want to look it up.
Marfa has a paranormal(to date, unexplained) sight. Look up Marfa Mystery lights.
you can park overnight at the rest stop 6 miles or so east of Marfa.. and see the lights.