I just did a summer trip along the West Coast USA. I was able to monitor my machines by using a pfsense router by allowing access to my home network with a IPSec IKEv2 virtual private connection. I used the built-in VPN connection on my iPhone/iPad to get into my local network and pull up the Apollo OS GUI via their local network addresses as if I was at home and on my home internet. The setup does take some effort but it’s not overly complicated (lots of good resources on the net), but it’s worth it especially when traveling or even just out the house for a while.