Peillon is about 20 minutes by car from Nice and around 30 minutes from Monaco in normal traffic. Parking near the old village is limited, and the final approach is narrow enough that summer weekends can be awkward.
The railway station is Peillon-Sainte-Thècle, on the Nice-Tende line. It sits in the valley below the old village, roughly 4 km away by road and about 200 metres lower. Walking up through the forest is possible and rewarding, but it is a real climb; the downhill return is much easier.