I brought wayyyy too many clothes last time. Just wash at destination. I always err on the side of less things usually and get along just fine. I bring a couple comfort items but leave gear at home if I can help it. Also, don't take no for an answer if the hotel says you don't have to reserve a PnP. I did that. They assured me that they always had enough. Well, guess what? They ran out and H had to sleep in a drawer (3 months old). I just didn't feel comfortable laying him on a soft squishy bed surrounded by pillows.
Also, if he sleeps with a sound machine you can download an app on your phone for that. Just have it plugged in all night.