You said you were pushing your mileage for a day, so...
I have a tendency to turn quick overnighters into long dayhikes, and long dayhikes with a late start into night hikes or overnighters. For those more ambitious dayhikes, I prefer to just pack for a minimalist overnight going in than think in terms of emergency gear.
No stove or extra clothing, but my shelter, pad, and quilt that will see me comfortably through a night in the 20s weigh <3.3lbs combined, and I'm not even "ultralight". My stuff for warm weather is about the same due to carrying the inner net for my shelter, but a lighter quilt.