I would also e-mail the leader, and politely mention that it "sounds like a great way for the girls to use the cookie money they all worked so hard for."
I am a leader...currently...but our troop is about ready to disband. So I will give you a little advice - sprinkled with GS troop money rules.
The troop money is owned by the entire troop. At that level, there are no "shares" of the troop that each girl would have earned individually. None. So the leader is extremely out of line taking the money and using it for something that not the whole troop has been invited to. (FWIW - if the girls are still a troop in their teens, they can do additional fundraisers, and have "shares of the troop money" if they are planning a big trip, but everything has to be spelled out and agreed in writing by all the girls and the parents.)
Anyways - handling this by e-mail should give you a either a response of "yes, there is a trip on Saturday, I'm sending out the info tomorrow" or no, we are not including your DD.
I would also ask her how the girls are going to be going through the park, from a "Safetywise" standpoint, and what preparations are they going to take, if someone gets lost, someone doesn't want to ride on a particular ride, how will the buddy system work with an odd number of girls etc.
If she doesn't allow your daughter on the trip (and you will have the e-mail to back it up) then find out who at your council office can assist. You may want to do a little research on the council's website, so you know how things are set up. Our council has service units (which break the council up into smaller zones), and then every service unit is divided up into schools - with a school organizer at each school. The school organizer & service unit manager are volunteers - which is why I would approach membership manager at a minimum. Our council website has all the names/titles/phone numbers/e-mail addresses - so contacting someone at the council office would be VERY SIMPLE to do.
Good Luck.