You're not REALLY going to rely on the responses you

receive here are you?

Hard to believe she is that stupid but, since she is leaving it open, I would ask her if her overnight rate times the number of days works for her.  I arrive at this based on the fact that you are not going to be boinking 24 hours a day on every day of the trip. Naturally you should expect to cover all of her expenses for the trip as well.

I would be very hesitant to enter into this arrangement without an agreed-to amount for the trip.

This is the way that hurt feelings and misunderstandings occur.

It is entirely possible that she actually means what she says and for all you know she might be willing to go without any donation whatsoever. OTOH she may end up resenting you if that is not her true intention.

You might try asking her (in jest) if that means that she is willing to go without any compensation. If she waffles even the slightest bit, get a firm agreement as to what a fair donation would be.

I'm just going to ask, what would she make in those 5 days.  Her being with you will take that money out of her pocket.  And this is on top of your paying ALL expenses, meals, travel, etc.  

This runs the risk of crossing the line between civie dating & pay for play.  Be very careful.
skb

Calulate the multiplier and use the average (or better yet, the median) of those multipliers and offer that to her.

I've done this a few times and never had a problem.

What is  very important is to always have the figure worked out before hand.

Do not assume.

This is one of the toughest things, when a provider will not specify a number.  I have an actual Fav lady.  Early on, I had to set a fee...  so now that is what she expects each time.  We have had a range of dates over the years...  sometimes I get a bargain, sometimes she does.  I guess it more than averages out. Fortunately it is a number we can both live with...  
skb