we are planning a 7-day trip to Guam with 6 people, 3 of them are teenagers.please advise on the following: 1. affordable Barrigada Guam hotel which is located minutes from the shopping and sights? 2. do we need to rent a car to visit sights or any day tours available? 3. where is Tumon Bay located? 4. good restaurants to taste the authentic Guam island food? many thanks.