Here's how I deal with her in a pretty reliable way. Freddy has a set path that plays out the same every night she's active, she'll go to five rooms and then attack. She moves at the same pace on night 4 that she does on night 6 and she does a little giggle every time she moves. She moves at a set pace too, and by 5AM she'll be in the final room and will have been for a bit. The moment 5AM hits, count to 20 or 25 and then close the right door until you hear another giggle. From there you'll be safe from her for the rest of the night and won't have to worry about her (At least up to day 6, I haven't gotten to 7 yet)
(Note: I never even use my camera on Freddy at all. In fact I only flash my camera on Foxy since the other two also have audio cues for when they are at the side doors)