Sure, that's true. I've never rented a car and been to Oahu staying in Waikiki. But an entire month anywhere in Hawaii is going to cost a lot more than the places they've mentioned enjoying in the past. If budget is a consideration.

Sounds like the OP has more experience than most of us!

Bali would be super if you can manage the airfare and the long trip to get there.

Coast of southern Turkey? (You'd have to check the temps so see if its beach weather)

Tunisian coast?

In both of those places you could easily get around for not much money with taxis and drivers.