What's the perfect island trip? (Jakarta)

Hi Jakarta expats,

For my mom's birthday in early November, I want to take her on a nice relaxing five-day trip to Bangka Belitung island (heard it's beautiful).

I'm having a hard time finding a nice resort/hotel on that island -- I'm based in U.S. and have never been do Indonesia.

Can any of you kindly give me some recommendations on resort/hotel/travel packages there, or to other nice quiet clean island in Indonesia? I'd be very grateful! I'm not looking for diving resorts, just nice, quiet, clean places near a beautiful beach. My budget is about US $100-$150 a night. Any recommendation or tips would be greatly appreciated.

Thanks!

Best,
Ella