The Gilmans substantially expanded the resort, which they owned until 1978. In 1913 they built a bathhouse and added a swimming pool the following year, which was later expanded to an Olympic size. A hotel was built to accommodate guests but had to be rebuilt after burning down in 1918. Many visitors came to Gilman Hot Springs by train via San Jacinto, where they were met by representatives of the hotel to be transported to the resort. By the 1940s, the hotel had 200 rooms. The resort also had a post office, garage and service station for the use of its visitors. Many cottages were also built at the resort for visitor use.