I will be in RA in Nov with thearenui.com. Thank you all for the report and it is helpful. I was born in Jakarta and I lived there until I was 15. I visit there once a year. My recommendation for solo female is to take city tour provided by the hotel or some known travel agent. Not many people speak English and not many sign are in English in Jakarta. Having a local tour guide that can speak English will help you. Don't bring too much cash when you are outside the hotel (50 USD is more than enough) and keep your passport safe with you (front pocket of your pants). Violent crime (rape, stabbing, etc) is not common there. All female member of my family always put their purse in front when they walk or even when they sit down and their guard them like tigers. They even wear the backpack in front instead at the back. We never wear flashy accessories (watches, earrings, necklace, rings) and no branded (Gucci, LV, etc) items. Oh, I always leave my iPhone, blackberry or other fancy phone back in USA and use simple cheap Nokia phone and bought local Sim card. You can text message or call home cheaper than using your foreign sim card. Nothing ever happen to me and my family so far but I heard many stories from my friend where they break the car glass in traffic light and grab purse and cell phone.
Other than that, Jakarta is a great place. Majority are moderate (not extreme) Muslims and they believe in doing the right things or they go to hell. I visited Taman Mini, Animal Safari (1 1/2 hours away from Jakarta), Istiqual mosque, Monas (monument national) and several museums there. I am a golfer and Jakarta is paradise for me.
One more advice, bring CRISP 100 US dollar bill that is F or G series. You will get 10% better exchange rate. You do not have to do that in Bali but in Jakarta is different. Every money exchange and even at big banks will only give you market rate if you have new 100 (not 20, not 50) dollar bill. I know it sounds nuts that's how it works.
Again, I think you should explore Jakarta with guided tour than spending 3 days at the pool.
Have fun.