Great places to thrive practicing permaculture in US are just about everywhere. There are things to take into consideration that may help you narrow it down.
Do you have friends or family in the area. Moving to a place where you already have a community makes an interstate move so much easier.
Look for a local culture that would be a good fit for you. Vacationing in potential locations is good way to get a feel for the place.
Make sure the level of government regulations will easily allow you to build and create what you want to build. Here in the northeast of the US the level of restrictions can vary dramatically not only the state level but also town by town. Can you legally run one or more businesses from your location. Zoning, permits, deed restrictions, land trusts, HOAs, and other land use restrictions can make your permaculture dreams a nightmare. What can legally be produced and sold can also vary greatly so it is worth digging through all the government red tape.
Water a huge item to consider. What restrictions would you have to deal in a location. Water rights, water harvesting, well access, wet land restrictions, and water usage restrictions vary greatly across the country. Avoiding flood planes is something I do. Knowing what the government allows or doesn't allow before you buy a property can greatly reduce headaches in developing a property.
What are you going to apply permaculture too? If you are planning on growing food with it what do you eat? Start making list of all the various ingredients you consume and figure out where it is easiest to grow them. Do you need tropical, cold wet, temperate wet, coastal or dry mountainous areas to grow what you already eat. It will also help you figure out how much space you need.
If the goal is to produce food how much time,
energy, and resources are you willing to devote to harvesting, preserving and cooking all of it. I am in a cold wet climate where the ground is frozen solid 4 months out of the year. This means a huge expenditure of time and energy into harvesting and preserving everything in the fall. Cooking everything from scratch from food you produced is awesome but it is an insane amount of work and often a huge shift in how you eat and it can easily be more work than growing all the food in the first place.