Wordpress and Dynamic Programming Php
My suggestion would be to use something like 'WP Super Cache' in conjunction with the proper structure as you defined above for your categories.
dentist
- alabama
- polk-county
- alabama
chiropractor
- alabama
- polk-county
- alabama
Making sure that each layer down has the "parent" of the above layer. This is a bit labor intensive to configure at first but should work for what you're looking for.
You'll end up with a url similar to:
xyz.com/category/dentist/alabama/polk-county/
If you want to scratch the category portion you can also create Chiropractor and Dentist as custom taxonomies and creating a custom '.php' file for them. The result of this would be:
- xyz.com/dentist/alabama/polk-county/
- xyz.com/chiropractor/alabama/polk-county/
WP Super Cache will make it so that the page doesn't have to load from scratch every time someone accesses it and should cut back on your server load.
Hope this helps!