What a great idea. I've been thinking about this too once I have more knowledge

It's great that you have the support of the management of your apartment complex too!! Congrats!!! Hope all goes well.
As for wording the flyer, are you doing a full or half page?? Including pictures of your previous trips? I would just say something to appeal to the most members of your complex.
If families: "Schools almost out for the summer and you're looking for something exciting to do with the kids. How about Disney? What?!? You don't think you can afford it? Not only can I show you the tricks to helping you save money, but tips to help make your day go as smoothly as possible. Give me a call/send me an email and we can get started on your trip today!"
If mostly singles/adults without kids: "Looking for a romantic vacation full of thrill rides, a walk on the beach and dinner with the most famous Mouse ever? Yes it can all be done at Disney and I can help show you how! Take a minute to give me a call/send me an email and we can start on your trip today!"
Just generic: "Thinking about Disney but think it's just too much to take on alone? I've been five/ten/twenty/whatever times and can help you have one of your best vacations ever! Give me a quick call/drop a quick email to let me know when you're going and we can start working on your trip today!"
Hope that gives you a little bit of an idea. If you're using a full sheet, you could either break up the page into two or three sections-one to get people to book a vacation, one for families who are already planning on going and one for adults without kids going. You could include some rides/restraunts/soemthing like that specific to that group that they would enjoy.
Again, good luck. If I think of anything else I'll post back!
