I just booked (last month) a London/Paris trip for my family of 4 with British Airways for April 2017!
Kids are 5 & 8, so we thought a whole week in a single city might not be the best for their potentially short attention spans.
The package includes flights from Newark, NJ, to London, London to Paris, and back to NJ. And 6 nights hotel (sharing a single room). They look nice, both are Novotel Hotels and both in decent locations.
Total for 4 people, including 3 legs of flights and 6 nights hotel, $3,094. I was pretty pleased with that price!!! I'm figuring another $900-$1000 for food and activities while abroad. Out of curiosity, I tried to book just the flights at ba.com, and the exact same flights (same flight days, times, numbers) were coming up as $14K total. (what?! I don't get it.)
I have been to both cities before, but I am very much looking forward to the Warner Bros. Studio (Harry Potter) tour!
Packages with gate1 travel and go-today.com insisted on putting the 4 of us in 2 rooms, ba.com did not. So my tip is to book flight and hotel together.