ds is a poor sleeper and very overexcited when we are there. We found best this was to sleep him in bottom bunk, and use spare bedding from top bunk to create a tent around the bottom bunk. This stops him getting so giddy watch what we are doing (lying on our bed saying 'go to sleep usually!') and helps him feel safe, as well as keeping it dark even if we have a light on.
Have a great time!