How can I use the same main site posts and menus on a subsite?

Hello good people,

I want to dynamically (automatically) copy the posts from the top level site onto a subsite. I.e. if a post is made then it should be copied to the subsite in real time, or near real time.

I'd also like to do the same with the menu-but that's not critical as menus don't change so often.

Additional info: I'd like the posts on the subsite to have the same name as the posts on the main site.

E.g. if a main site post was named, dated for today as, "April 4, 2012," and so the permalink was:

mysite.com/april-4-2013

...then I'd like the subsite post URL to be:

mysite.com/subsite/april-4-2013

I know you guys are super geniuses and helpful-I hope something like this is fairly easy to do :slight_smile:

Thank you,

Chris