It has been previously established that high cognitive load influences driving performance, but is the driver's perception of their experience while driving also influenced by cognitive load? To our knowledge, little evaluation has taken place regarding the investigation of such an effect of cognitive load on user experience, especially in the automotive domain. This paper introduces motivation and background of our current research on real-time monitoring of drivers' mental states aiming to explore the previously mentioned relations between mental states and UX in a driving simulator environment. Furthermore, the paper presents initial ideas of task designs that are targeted to elicit and induce mental states like cognitive load and selected user experience factors we consider being interesting in the automotive domain and that we aim to discuss with other researchers and practitioners in the workshop.