Complex sentence: In 1891 visitors traveled the lower Mammoth road through what is now the main residential area for park personnel and the guardhouse was the first building they encountered in the Mammoth area and there was always a sentry on duty here to check visitors entering the park.
Split into simpler sentences: In 1891 visitors traveled the lower Mammoth road through what is now the main residential area for park personnel. The guardhouse was the first building they encountered in the Mammoth area and there was always a sentry on duty here to check visitors entering the park.