If you do a search for 'abroad', you will find several threads on this.
But you've done the first thing - you've already met him! You also know you can stand an extended booking with him, and that he should leave you alone for several hours a day.
As far as cost is concerned, it is as ever up to you. It is going to be at least seven days with no other income for you. What's that worth for you? If someone handed you several thousand pounds, would you book five days there? If not, you may not feel that the location matters in terms of what you charge.
Ideally, you get enough money upfront to book a ticket yourself. (Otherwise, there is an issue of how do you protect your identity etc.)