Caedra may hope for that, but she might find that it is extremely difficult for an external force to gain entry to Arda. That universe is guarded by the Wall of Night, beyond which is the Void. When the Valar finally went to war with their brother god, Morgoth, to prevent him from destroying what was left of Middle-earth, they threw him into the Void, where he forever roams in fury and hatred but cannot get back in. Caedra would not only have to get past the Wall, she'd have to get past Morgoth! He's a sort of involuntary watchdog, a very fierce one.

But we do not know, since that day has not come.

Curufin listens to her answer to his question.

"Yes, it's called cabin fever, in the Common Speech. Apparently our worlds have that in common. Nobody likes to be confined. Do you have some way to travel amongst the islands here?"