Better free to fly or enjoy the scenery?

I'm going to be a guest for 10 days at friends and bring the 2 boys. They are used to flying free in my studio. Should i put them in a room (the garage) where they can be free to fly back and forth to their cage and keep them there or should I keep them in their large cage and bring them outside to the gorgeous garden where they can enjoy the local birds but must stay in their cage obviously. It's warm and beautiful here.