The Earliest Buddhist Shrine: Excavating the Birthplace of the Buddha, Lumbini
By Robin A. E. Coningham, K. P. Acharya, Keir M. Strickland, Christopher Davis, Mark J. Manuel and others20 pages
excavations revealed a sequence of early structures preceding the major rebuilding by Asoka
See this post by Bhante Sujato explaining that it’s quite expected that Maya would haven given birth at a pre-existing shrine. And see this response by Richard Gombrich further refuting the paper’s proposed chronology.
Still, the paper does inform us a bit about the site as Maya must have found it: a ~200-year-old outdoor shrine with thick wooden fencing around a central tree.