Just returned recently from a week in Aruba. We stayed at Playa Linda.
If you are going to be cooking, I would definitely rent a car (we normally do, but on this trip, we did not).
There are a number of reasonable restaurants right in the area. We ate at Salt & Pepper and Fishes and More (right across from the OC?), and there were two or three other places in the same place which looked reasonable.
Madame Janette's (arguably, the best restaurant on the island) is an $8 cab ride in each direction, and it is one of only two restaurants on the island which have cabs waiting almost all the time (at least, that's what our cab driver told us).
Some of the stuff you might want to see would be rough, if not impossible, with anything other than a 4WD, but you can take a day tour in one and see it all (we saw the lighthouse, although not at sunset, the church, the smelter ruins, the natural pool, baby beach, ??).
I think we took one other cab ride (a snorkeling trip out of Oranjestad), but that was it. If you are happy lounging around on the beach (Palm Beach is very nice),...
I suspect we will probably rent a car the next time we go, but, for this trip, we were fine without one.
Tom