I'm going on my first solo trip in less than 2 weeks. Booked a week (7 nights), which seems perfect to me! Last trip, 5 nights, was supposed to be solo, but DH decided to come along (so this is a kind of a do over, LOL). Since I have the AP, I decided one more trip was in order!
Most trips with kids have been 7 nights typically, but longest was 15 nights (off site, but it was so relaxing as we had a condo very close by, so spent some days just chilling).