When we travelled this past July, my son had a great deal of difficulty settling into his new room. Although it can be time consuming, and may not be any better than what you've already tried, I would sit in the room with him but not lay down with him. This was especially helpful if he was hysterical (not just fussing). I would sit where he could see me but in such a way that he could not see my face (that seems to keep him engaged). By doing this, he was able to finally settle himself down without requiring much from me. Every couple of minutes, I'd move a little further from him & a little closer to the door.
Now, if he is fussing, whining, and just dragging bedtime out, I do it a little differently. I'll lay him down. If he's pretty noisy, I'll wait 2 minutes before I check on him. Then leave. Then I'll wait 4 minutes before I check on him. Then leave. It usually doesn't require much more than this. In the rare event that it does, my next visit is 6 minutes later. At this point, almost 15 minutes have passed since first laying him down. If he's still pretty fussy at this point (again, very rare), I'll go back over the checklist (make sure he's not thirsty, dirty, wet, in pain, temperature is comfortable, etc).
Try a few, find what works for you & your family. Best of all, you're seeking advise and there were alot of good suggestions I've read here already.
Good luck!