How can i get the lists for the authenticated user & the lists that user follows
This should work:
var service = new TwitterService();
service.AuthenticateWith(<your consumerKey>, <your consumerSecret>, <your token>, <your tokensecret>);
var listsUsersLists = service.ListListsFor(listOwnerScreenName);
var listsUserIsIn = service.ListListMembershipsFor(listOwnerScreenName);
var subscribedToLists = service.ListListSubscriptionsFor(subscriberName);
As long as the authenticated username is the same as the name of the lists you are trying to return, private lists will be included too.