Also, just two short blocks from the Albergo towards Piazza Navona, you will find the church of San Luigi dei Francesi. It has some magnificent Caravaggio paintings on the chapels down the left aisle near the front. Free admission.
From there, just walk the short distance to Piazza Navona and walk around.
With any luck you will be able to get to your room earlier than you think. A lot of people leave early for their flights or cruises. That was our experience this summer when we got our room around noon