The easiest way to solve this is to have a collection for the information you want to get with the sign up questions. Then have a field in that collection that is initially false and is only set to true when they answer the questions. Then you have a before route action that checks whether it is set to true before going to the home page and if its false it goes to the first time login page. This makes it easy since when they submit their answers (you set the value to true) and then redirect them to the home page and since its now true they will go directly to the home page instead of the sign up page.
If you haven’t decided on a router Iron Router is go to router that most people use, though there is Flow Router which is more light weight but also has less features.
Have you had a chance to go through the Meteor tutorial on the meteor site? Discover Meteor is also a great resource and it worth the money. Though if you are looking for just free resources there are a bunch too pick from http://meteorhelp.com/