First Time Paris Questions

[superdisneyfan]

We may be going to Paris for the first time in September and being huge Disney fans, we couldn't go to Paris without seeing DL Paris. Of course, coming from the states, we must do all the touristy things in Paris as well and I had thought we could do all of DL Paris in one day. Now, going into the website, I find out there are 2 theme parks there and 7 hotels so it's not such a small place as I imagined. If this is a once in a lifetime trip, how many days should we spend there and where should we stay? Should we stay by DL for the day(s) we are there, or should we just stay in the center of Paris and take the train? How long does the train take and how often does it run? We figured we need at least 3 days to see the Paris sites alone and then we would also want to see another country. Any suggestions for a newbie in Europe is appreciated. Thanks!