I just rent a boat when I go, but I would head toward Islamorada and try Bud and Mary’s Marina or Robbies Marina for a guide. June is a prime month for tarpon and you should be able to get a shot at one on a half day trip. For offshore, you should be able to catch dolphin and tuna with the possibility of other species. I wish I could give you a name, but the guides I have used are retired or have passed away. If you just want to get off and catch something, there is a party boat the goes out of Robbies. It is called the Captain Micheal. You can catch snapper and small bottom fish. You can also get barracuda, king mackerel or yellow jacks if you are lucky. I always take a big rod to catch nurse sharks, just to get a big pull.
The trip to Robbies is worth the drive just to feed the tarpon if you have never done it.