To the ancient Egyptians, the Land of Two Fields was a real place. It was a heavenly place. It was the place you went after you died. One of the reasons the god Osiris was so honored in ancient Egypt is because it was Osiris who opened the door to the afterlife for everyone.
It took more than dying to enter the Land of Two Fields. You had to earn your way into your afterlife by doing good deeds while you were alive. The more good deeds you did, the lighter your heart became. If your heart was not light, you could not board Ra's board and sail away into your Afterlife. To avoid any chance of trickery, the goddess Maat weighed your heart after you died. If your heart was not light enough, you were stuck in your tomb forever. But once you were in, you were in. You only had to sail away in Ra's boat once. After that, you had a free pass, and your soul could come and go. There was not a lot of crime in ancient Egypt. Everyone wanted their heart to be light.
There were two other requirements you had to satisfy before you could enter the Land of Two Fields. Not only did your heart have to be light, you also had to have your name written down somewhere, and you had to have a preserved body. That's because the ancient Egyptians believed in a soul. They believed your soul split into two parts after you died. One part, the Ba, flew off every morning to keep watch over your living family. The other part, the Ka, flew off every morning to the Land of Two Fields, to enjoy your Afterlife. Both the Ba and the Ka returned each night to your tomb, so you could get some sleep. In the morning, the cycle started again.
If something happened to your preserved body, or if your name was not written down somewhere, the Ba and Ka would get lost on their way home. You would disappear. You would never again be able to watch over your family, or be able to enjoy your afterlife.