Hi Grant,
A lot of people do rent cars when visiting Aruba, I have been to Aruba many times and never rented a car --I'm sure it's more convenient, but you can either take cabs, that can run expensive OR there is always a bus that stops at all the hotels that's really cheap, like a dollar something each way, it runs I believe every 15-30 minutes throughout the day and stops at maybe 11:30pm. You can enquire about the location of the bus stop, but it's probably right in front of the hotel. I have never stayed at the Marroitt, but I've stayed at the Holiday inn right next door and I know there's a bus stop right out front--so i'm sure there's one in front of your hotel.
hey, ENJOY!
My sister and I, who are in our 20s, will be visiting Aruba from July 14-31 this year, and I can not even wait!!
OH, one more tip --I learned this after the first couple times visiting there, don't bothering spending lots of money on bottled water, you may have even heard this before, Aruba has the purest water, so fill a couple water bottles and call it a day--you'll save soo much money---If you want to research that fact, please do--I believe there have been people that have posted info about Aruba's water on this site--
Have a great time!!!!!!
~Nik