Creak, pop noise?
Have you looked at the frame underneath? One possibility is a cracked frame, and it typically happens on the A-frame near the front of the cabin. If that's the case, don't despair - it's fixable and several other forum members have experience to help (Norm, aka honda03842, comes to mind). I'd look ASAP, though. If it is cracked, you don't want to be pulling it anywhere.