ChuckT, I might be chimming in late here but here's a few thoughts.
You have seen her only 2 times and now your going to spend a week with her. You may be the nicest guy but lets face it the ladies are always cautous of clients. A favorite told me that for overnights they really don't sleep much because they never know if the guy is going to snap so they keep their guard up all the time. After days of this your date is going to get mighty irritable due to lack of quality sleep. You may have some chemistry but still you are escentially strangers. Others have mentioned not to expect sex all the time, they are probably right. If you decide to go through with the trip make sure you have a discussion with her asking her opinion of how she envisions what she wants to do on a daily basis. She may have a totally different concept of what the daily life is going to be like from your vision. I think you need to spell it out to a itinerary, sleep, fuck, breaky, sightsee, lunch, lounge, fuck, etc. She may be thinking sleep breaky, lounge, dinner, etc. Any type of mismatch will make for a very awkward trip.
As far as rate goes, I never believed in telling an SP what they should charge, just ask her what she wants. If your good with the rate go for it, if its out of your price range then say thanks but no-thanks.
my .02