The Historic Khorramabad Valley, one of Iran’s oldest human settlements and a UNESCO World Heritage Site, holds exceptional natural and cultural tourism potential, yet faces barriers in infrastructure, marketing, and planning. This study aimed to determine the optimal combination of tourism infrastructure, destination marketing, and cultural-recreational events to maximize tourist attraction using Response Surface Methodology (RSM) with Central Composite Design. The sample included 101 tourism practitioners in Lorestan, assessed via a 9-point Likert questionnaire under hypothetical scenarios. The quadratic model (R² = 0.9638) was optimal. Results revealed marketing with the strongest linear effect (coefficient 1.23), infrastructure with positive quadratic effect (increasing returns), and events with negative quadratic effect (diminishing returns beyond optimum). A positive marketing-events interaction indicated synergy. The optimal mix infrastructure and marketing at level 9, events at 8.015 yielded 7.98 attraction. Findings underscore the need for integrated, data-driven sustainable tourism planning. Recommendations include forming an inter-sectoral steering committee, phased infrastructure investment, smart marketing, and optimized event management.