I will do anything to keep from going through this again. I still look like I am diseased, although it is getting better looking each day. I am in the process right now of washing everything that was in that suitcase that was in the freezer as I type. I am willing to use whatever means I can, and your suggestions sound like they would be worth using. And I will travel there with sulfur for dusting my clothes next time...but where do I get that?
I only had one thing that I was not sure about in your post, and that is the "put the clothes you were wearing in a hamper far away"...I would suggest burning them.
Actually, I would not do that---I would not leave anything with possible chiggers laying around at all. I would put them in the washer as soon as I got home and wash with hot water, before I even went to treat myself and shower. I would also put my shoes in a plastic bag and put them in the freezer, just in case. Better safe than sorry....you sorry is what you will be if they get you.
I am sure that I will be in chigger territory again, but maybe I will visit my sister at a different time of year next time. Or maybe she will move.