Away from LO for 24 hours.. Pump Schedule?

Vegasbb

Please no flames or judging. As a birthday gift, my Mom (who has cared for DS here and there since he was born) will be watching DS for 24 hours so DH and I can go away for my birthday. I haven't had more than 5 hours of sleep since I got pregnant so I'm very excited. LO will be 4.5 months old. LO is great about switching from breast to bottle and back. 

I'm bringing my pump, but would like to pump as little as possible during 24 hours to just keep my supply going.  I haven't had any engorgement issues since the early days (LO sleeps from 6 PM to midnight and I often don't pump during that time and get "full", but definitely not painfully so). So assuming I have no "pain" issues, is pumping every 6 hours going to be enough so that I don't "dry up". Does one "dry up" in a day? Do I have to pump every 4 hours? At 4 months is my supply relatively "established". Would love advice ! Thanks!