Is there any advice for a group of gals going to bangkok for holiday? (such as areas to avoid, etc)?

It's common for some tuk-tuk drivers and non "meter taxis" to offer to show you around the city for a very low cost. They will take you to a series of places where everything is overpriced (they get paid to bring you there, or a percentage of whatever you purchase). If you wish to take one of these tuk-tuks or cabs you should be firm in telling them where you want to go. Alternatively, you can avoid being dragged around by only taking the official Meter Taxis.