It depends on what you mean by “manage”
While the Internet is off-line a few things will run, not too many. Notifications will stack up and then be sent all at once when in and it does come back on, which can be quite confusing.
It’s supposed to be that when the hub comes back everything goes back to running. However, many members report that after An outage, scheduled events remain scheduled for the past and therefore do not run. This requires opening the SmartThings mobile app, looking at each scheduled event, and saving it again. How much that affects you depends on how many scheduled events you have. But at least that step can be done remotely.
In other cases, some devices either drop off the network or to get stuck in a specific reporting mode, like a motion detector that is constantly reporting motion. Those fixesvrequire resetting the individual device, usually by removing the batteries and putting them back in again.
SmartThings staff has posted that engineering is looking at these issues, and presumably some improvement can be expected in the future, but there’s no specific timeline for fixes.
So it’s hard to say how much your vacation home would be affected. It really depends on the exact automations you have set up to run. It might be that Everything that would work very well for you, or it might be unacceptable.
My biggest concern in your specific case is that many of the current fixes require taking the batteries out of battery-operated devices and putting them back in again to resync everything. That’s obviously not going to be possible if you’re not physically at the home.
So I would say that it’s intended to be able to handle that kind of situation, but at the present time you have to evaluate exactly how you using it because it’s not hitting the mark completely right now.