One-day trip to Hanoi and Halong Bay, Vietnam?

1. Safe. Don't worry too much. 2. Yes, but it is very expensive. Go to the Island Park in the center of ha noi (I don't know the name of the lake, which is very famous in Hanoi) and find a travel agency to take part in the tour. Tell them the name of your hotel and they will pick you up in the morning. Individuals don't know what group they will be assigned to, so they can't choose. Never encountered forced shopping. 4. That's enough. I just took a one-day tour. The two to four-day tour is to stay on the boat. Yes, it is ok to have a temple in the cave, but I forgot the name. Just look at the leaflet of the travel agency. 6. The hotel has it, but the exchange rate is not good. You can change it on the street yourself. You can join a group tour in dollars. I haven't tried using RMB, and I don't know if I can use it directly.