Tracking registered user activity

Hello,

I have 2 questions:

A client has asked me to create a site where users can register to view certain posts. Only a post excerpt would be viewable to non-registered users. He would like a customised registration form where a few questions are asked such as, say, the sector in which the user works. Registration is free.

He would then like to be able to see that user’s activity i.e. Bill Smith has visited pages X & Y and commented on post Z.

I’ve been looking at a few premium membership plugins but they probably do too much for what I need and none of them have customisable registration forms.

So..

1/ What would be the best solution to allow users to register to view certain posts.

2/ is there any way of viewing registered users’ activity on the site once they are logged in?

Thanks for any suggestions ??

Jonny.