Question: I would like to know if I can stay two months out of the United States. I have a TD visa and my dad has a TN visa. I would be the only member of the family traveling.
Reply: As long as your dad continues to maintain his TN visa status (i.e. is still working for his TN employer), you may continue to travel and re-enter the U.S. for the duration of your TD I-94 record. If you are not a citizen of Canada, then generally you will also require an unexpired TD visa stamp in your passport to re-enter the U.S.
If you will be out of the U.S. for an extended period of time, when seeking re-entry to the U.S. it may be beneficial to have (1) your original birth certificate plus any needed translation; (2) a copy of your dad's TN visa support letter; and (3) copies of your dad’s recent pay stubs as proof of his maintenance of TN status.