I have a home page that I like for guests to come across, but my existing users would prefer to see a home or dashboard page with more widgets and site activity upon visiting. 

How can I code a redirect into my home page for logged in users? Ideally this would happen before the page fully loads to save time. 

A redirect is not a good solution. Just change the permission of the blocks you have on that page so that one set is shown to guests and not members, and the other is shown to members but not guests.