Tips for shooting nude, outdoors?

I have a very close friend who's asked me to shoot nude shots of her. Ideally, she'd like them in a forest or near a river, during a time of day with good light. (Probably dawn/dusk lighting). I still have to scout the location, one where we won't be bothered at all, but can still get to.

I'm still a learner, self taught and testing new things. She knows this and knows my style.

She wants it to be as natural as possible, but still sexy, know the kind I'm referring to?

I have a D3000, tripod and the kit lens. I'm getting a 50mm 1.8 before Christmas that I am hoping to use on this shoot.

I've shot people before, always in natural lighting. Any tips for a nude one though? Good positioning? Best this or that?

Examples; 1 2 3 4

Thanks everyone, in advance!

EDIT- I won't have handheld/standing lights, reflectors, umbrellas, studio anything.