Iguanas roam esp. in breeding season, and when their environment gets changed. When you plan your searches, think "close". She is most likely to be close by. If she's outside she is most likely to be hiding next to your home's foundation. Wherever she is, if she's cold, she won't be traveling at all. Be careful, as you can look right at her and not see her. Hopefully she's in the house. You have already done an excellent search job.