Live in Idaho. Want to move to Tx. w/kids. Don't have 60 dys to wait for ex to contest. Can I serve him, move and return for crt

My husband lost his job & I'm loosing my house. Waiting means running through much needed funds for the move and being without a place to live. My dad offered us to stay with him. He has 3 xtra bedrooms- plenty for us, until we get working and into a place of our own. Jobs are scarse here but plentiful in Texas. I sent my ex a certified letter and he refuses to sign for and receive it. I know I can have him served by an officer but don't have time to wait. He's threatening to take me to court to stop the move or for custody if I do move. Even though I don't have a house now I will within a month of the move. Can I serve him, move now and return for court if he goes forward with his threats? What are his chances of getting the kids? He lives with his convicted sex offender brother-2 bedrms