Travel at 5-6 months

Hello ladies!!! So I received promising news today that I am about 5 weeks pregnant! My husband and I booked a cruise that will require A LOT of walking everywhere in old European cities with lots of history tours. I'm fairly fit, run a lot and enjoying walking (for now). I'll likely be about 5.5 months by the time of our trip... What are your thoughts on walking around while pregnant that far along?