The chapter presents the main results of three research projects developed in the last years in the context of Balkan and Eastern European Countries: Interreg South East Europe Access2Mountains, which regards Alpine and Carpathian regions; Interreg Italy–Croatia MADE IN-LAND and Interreg Italy–Croatia BOOST5, which interests Italian and Croatian Regions. These projects' main objective is to enhance the protection and valorization of natural and cultural unexploited capital of inland sensitive regions by means of environmentally friendly tourism development and improved (sustainable) accessibility. The chapter will provide insights into the regional development of regions understudy, focusing on specific local challenges: on the one hand, the fragility of the tourism sector being highly fragmented, imbalanced, and still with low digital intensity; on the other, the lack of sustainable alternative mobility solutions to serve tourist itineraries. Project results demonstrate the importance of data-driven policymaking and the role of data in understanding specific criticalities and in shaping and guiding decision-making. In this framework, the projects foresee the deployment of a systemic approach and common methodologies for natural and cultural enhancement to: eliminate main obstacles limiting the full development of sustainable tourism offers; promote community-driven ideas and new market opportunities through capacity-building plans about innovative approaches, sustainability and managerial skills; promote synergies among diverse stakeholders and territories to speed up successful implementation of sustainable accessibility policies and environmental awareness; pave the way for the next strategic steps such as green accreditation or zero-impact tourism labels and building on next programming period opportunities.