Cash out refi to pay off second home

[Jeremy Schneider]

Here’s my situation primary mortgage 330k worth 900k+ sitting at 4.375% fixed

Second home (cabin) 240k loan 3.5% fixed. we are planing on moving to the cabin full time in the next 3-5 years. With the great rates right now and our equity thinking of cash out refi on our primary to pay off balance of second home. When we eventually move there full time our primary would become a rental home. 
thoughts?