Advice for a first timer

Hi all. We have around 50% equity in a $320k property and are planning to build a new house and keep the existing one as a renter. My wife and I are both wage earners and want to live in the new house for 1-2 years then sell it and repeat the exercise. Would our discretionary family trust be the best way to structure the loans, or is there a better way to go?

Thank you for your comments.  Graeme.