Texas Hwy 90 - Safe for Solo Woman? (S.A. - Van Horn)

it's a good way to go and as safe as any other route. there is some traffic, enough that you won't feel all alone in the world :)

Marathon is a nothing little place but it has a decent RV park and a very nice restaurant at the old Gage Hotel.
or Spend the night at the Marfa lights viewing site... a nice rest stop about 6 or 7 miles east of Marfa. You'll have traveling company.