You are safe. Make sure to carry your DACA work permit with you.
Mr. Shusterman's (former INS Trial Attorney, 1976-82) response to your question is general in nature, as not all the facts are known to him. You should retain an attorney experienced in immigration law to review all the facts in your case in order to receive advice specific to your case. Mr. Shusterman's statement above does not create an attorney/client relationship.
Yes, you are "safe" indeed. Make sure to have a CA issued state ID or driver's license, your employment authorization card, DACA approval notice (Form I-797 notice of action.) You are better off flying from SF or SJ or Oakland to Houston, where all you'll need to show is your valid state of CA issued ID (without anything more!) For a road trip, you'll need to carry all the above documents with you, for there you'll be dealing with CBP and Border Patrol checkpoints rather than simply with the TSA at the airport, who are clueless (and not at all interested to know) about one's immigration status or lack thereof.
Kindly be advised that the answer above is only general in nature cannot be construed as legal advice, given that not enough facts are known. It is your responsibility to retain a lawyer to analyze the facts specific to your particular situation in order to give you specific advice. Specific answers will require cognizance of all pertinent facts about your case. Any answers offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship.
Do not worry one bit. Always carry your DACA approval notice, EAD, ID and possibly a copy of the approved I-130 with you and you should be fine. While close to the border, Houston is still located in the U.S. and therefore U.S. laws and regulations - including the government agreeing to defer action in your case - apply.
This advice does not form an attorney-client relationship and is merely informative. It should not by itself be relied upon to address a legal concern.