Mentorship and collaboration necessarily shaped opportunities for women in science, especially in the late nineteenth century at rapidly expanding public co-educational universities. A few male faculty made space for women to establish their own research programs and professional identities. At the University of Minnesota, botanist Conway MacMillan, an ambitious young department chair, provided a qualified mentorship to Josephine Tilden. He encouraged her research on algae and relied on her to do departmental support tasks even as he persuaded the administration to move her from instructor to assistant professor in 1903. Resulting publications on Minnesota algae led her to look further west, first at Yellowstone National Park and then along the Pacific Northwest coast. After visiting a particularly productive littoral site on Vancouver Island, she suggested that they establish a Minnesota Seaside Station there. Over its seven years in operation under the Midwestern leaders, that location proved remarkably productive. At the remote site, the two operated within their typical but not inevitable gendered roles and deliberately defined their seaside station as unconventional. They expected participants to study productively and, at the same time, find imaginative ways to enjoy nature at a place far from urban amenities. Gendered expectations remained casual as participants moved both within and against them. This study investigates how, in the early twentieth century, the role and expectations of mentorship shifted as Tilden established her own independent research agenda. The Minnesota Seaside Station, in particular, proved significant in developing the leadership skills essential for her to pursue research in the Pacific region at a time when American expansionism and indigenous cooperation made sites accessible to academic researchers.