How to estimate travel expenses?

Hey guys,

I am a brand new kid on the block for investment management and I haven't been working long enough to know how to deal with this.

So I am trying to get my boss to send to a foreign country to meet with some of our contacts there and he said it was a neat-idea and told me to prepare a proposal with the estimate cost.

However, I am not sure how to do that, I plan on staying about 4 weeks, moving around in the that country quite a bit and the easiest way for me to access funds would probably be just having them give me the money advance.

The question is how much do I ask and how do I correct "estimate" my expenses?

Thanks

Ben