Travel Office Commercial Travel Office (CTO) is located at 9th Street Bldg. 15, Barstow, CA 92311. Travel Office Commercial Travel Office (CTO) can be reached by their main phone number at (760) 577-6135. Alternatively, you can reach Travel Office Commercial Travel Office (CTO) by phone at (866) 711-9575. You can also reach Travel Office Commercial Travel Office (CTO) by phone at (877) 332-1543. The listed DSN line is 312-282-6135.