Many states publish their administrative codes online. Westlaw and LexisNexis include state administrative codes, as well. For official names (e.g., Utah Administrative Code, Code of Vermont Rules), see Table T.1 of the Bluebook.
You can access state agency decisions and guidance on Westlaw, Lexis Advance, and Bloomberg on the same web page that you would access the state regulations. It will be under "Administrative Materials" or "Administrative Decisions." You can also obtain the agency's decisions off of their website.