Whenever I don’t rent a car and want to do excursions from Aulani, I book the excursions they offer because most of them pick up at the resort. Sometimes you can call the vendors yourself and book the same excursion, but most require minimum numbers to go. The excursion desk at Aulani can tell you the minimum number for each and what the likelihood is that it will run. Keep in mind that most tours pick up in Waikiki, but very few pick up in Ko Olina which is where Aulani is. If you‘re planning to go to a lot of places that don’t offer tours or don’t pick up at Aulani, you’re better off renting a car. To find out Uber prices, go to the Uber estimate website and put in where you want to go and it should give you an idea of what it will cost. Good luck.