There is good water anywhere there is water. Before suggesting where to go I'd be asking what you 2 want out of the trip? How do you guys like to fish? What is a short CV of where you have been before? Where are you guys on the "any day fishing is better than working" vs. a good day is when I catch a big fish scale? Peeing over the side of a flats boat is kinda lame for a 65y/o guy with prostate problems. Any physical limits? Are you willing to gear up for the planned fishing or do you want to stick with the gear you have? Going to Florida in summer is pretty rough weather baking on a flats boat. Yellowstone is a higher elevation volcano and much more mild in the summer and the 45F water is A/C in your waders. Are wives going to hang out? More to do and see for non-fishers in Yellowstone vs. Florida but if your dad is a car guy you could do a trackday at famous tracks like Daytona or Sebring to break up a week of fishing. If you guys hunt you can also do a "cast & blast" to break up a week of fishing.