We stayed one night at the inn, then set off the next morning.
Tips
usage
The 宿 here takes the night-classifier reading xiǔ, not sù ('lodge'). This reading is used almost exclusively as a counter - 一宿, 两宿, 三宿 - and colors a stretch of time spent through the dark hours.
register
Colloquial, common in northern speech. In formal writing, prefer 一夜 or 一晚.
