We stay at the Marriott next door, and I cook a lot when we're there. I do lots of things on the grill, whatever the family wants (one trip 3 years ago we had a large group, 12 in all at one point in our own villas, so we did a couple of large dinners to share - I got boneless skinless chicken thighs and Yoshida's sauce at Costco, marinated them in large ziploc bags for a couple days, and we had a ton of chicken teriyaki). We also get frozen burgers at Costco - easy to make. We usually get a veggie tray from there, some salads, fruits, and sometimes sashimi.
Also Target has things for breakfast, rice, seaweed, juices.
I try to have a plan for a few meals ahead of time, so I can pack some spices. We tend to stay a long time (always it's been 2 weeks every other year, but next summer I'm going for 4 weeks with my DD, and my DS and DH are coming the last two weeks). I'd rather eat healthy and not spend a fortune eating out! I also bring other kitchen items sometimes, and buy things like Pam cooking spray for the grill and making eggs, nonstick reynolds wrap, but I can bring ziploc bags, food storage containers, extra tongs, etc....
Sometimes I'll make a pasta salad - cook pasta, rinse and cool it, toss tomatoes and cucumbers sliced up and add italian dressing (and I like to add Spike seasoning - it's my go to spice, great on meat and fish too). Let it sit at least a few hours & it's a nice side dish.
We do most of our shopping at Costco and Target (or
Walmart). I don't care for Safeway on Oahu, but if there's something I need that can only get there I'll go.