Early detection of subclinical vascular alterations is critical for effective cardiovascular risk stratification and prevention. Arterial stiffness (AS), a hallmark of vascular aging and hypertension, is a strong, independent predictor of cardiovascular morbidity and mortality. While carotid-femoral Pulse Wave Velocity (cfPWV) is the non-invasive gold standard for AS assessment, it requires skilled operators and involves some procedural risks (e.g. plaque disturbance), limiting its broader clinical and ambulatory application. Optical timing-based approaches offer safer and more practical alternatives. This study presents a comprehensive evaluation of Pulse Arrival Time (PAT) at five peripheral arterial sites—carotid, temporal, radial, digital, and tibial—to explore their potential for non-invasive vascular assessment of AS using photoplethysmography waveforms (PPGW). Three complementary aims are addressed: assessing the feasibility of acquiring PAT at these sites using PPGW, conducting an in-vivo study to assess the reliability of using PPGW and electrocardiographic (ECG) signals acquired from a demographically diverse cohort, and comparing obtained values and estimating age-related changes in estimated PAT from a validated in-silico database. The temporal arterial consistently demonstrated favorable characteristics, including high-quality signals and clear associations with age and disease status. These findings position the temporal site as a particularly favorable candidate for the development of non-invasive diagnostic tools for early vascular aging detection, broader cardiovascular risk screening, and the expansion of the cerebrovascular assessment frontier.