I will be away from my email for about six months. I don't want any of the emails in that time to be in my Inbox when I return.
Is there a way to set up a filter that will send all incoming emails to a separate folder for a date-limited time?
No, you cannot setup a filter based on a time period.
You could setup a filter to send all of your mail to the Archive (and also label them if you want) but you would need to turn that filter off once you no longer want it active.
Inbox Pause (inboxpauseDOTcom) will do that for you. The app is intended for more a more frequent pause/resume toggle. If you just want to take a 6-month break, the suggestion above to create a filter for all incoming email that skips the inbox and applies the label/folder you want is the right one.