(Plus a simple itinerary + neighborhood guide you can actually use) My first trip to London with my two children, I learned a few things. A few hard lessons. We are heading to London for spring break for our third trip, and I have always found it impossible to find a hotel room that fits three of us. I noticed widely across the UK, rooms have king beds but say they fit three people, or two twins, which say four people. If you have kids or kids far apart in age, like my son being 14, he is not going…