some states require that any rotation done inside the US must be done at a hospital with ACGME residency in that specialty (eg. for surgery, you must do it at a hospital with an approved surgical residency). that being said, some states do not require this. for example, California only requires that your rotations are done in a hospital with a ACGME family practice rotation.

another option is to do it outside of the US at a hospital affiliated with a med school. I am doing a surgery rotation in south africa that will qualify in any state..

the best bet is to do it at an ACGME or outside of the US. that way you will not be limited where you can obtain a license or do a residency. if you can't arrange it yourself, go to pgy1md.com or clinical-coordinator.com and they will hook you up for a price.