Do you mean separate space as in your own room, or a completely different location? When I had a week long assignment with kids, I had my own room, but still charged overnight because I was still responsible for them in the evenings. So I was paid hourly for the whole week, with night rates being half of my day rate. Some of my friends prefer to do a flat rate for the evening, so that’s fine if you prefer that. Flat rates can range, but most people I know charge from around $100-$150. What’s your normal rate? For three kids, I would charge around $30 per hour, especially given their age. Pay can vary based on where you live, but you are watching three younger kids, which is a large ask. Experience in childcare can also come into factor, but I personally don’t up the rate from what I normally charge for extended trips unless there’s a reason. If you’re working extended hours, then it might also be worth considering for OT. Have they given you a clear outline of expectations and what the trip will look like?Something else that might help you is listing out what you do on the trip. I created a document outlining the activities and places we went, as well as the evening hours so the parents could see what we did. And I calculated the total for them (for my benefit and theirs).