DataSource Controls :: Entity Framework And Architecture Of Model - Create Application Using EF

I can't to understand clearly how to create strong and quickly application using EF. For example, I have class ForumPost (table ForumPost) for select one of record I write method like:

public ForumPost ForumPost(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
where i.ForumPostID == ForumPostID select i).First();
}

all works. But on page (I use ASP.NET MVC) I should display info from another linked tables, ForumName (each post have ForumID) etc. So, I modify this method to:

public ForumPost ForumPost(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
.Include("ChildPosts").Include("ParentPost").Include("Users").Include("Forums").Include("Tags").Include("ForumPostPolls")
where i.ForumPostID == ForumPostID select i).First();
}

ok, all works. Then I want to make some actions in model with ForumPost, i.e.

public void RootPost(int PostID, ref Models.ForumPost Root)
{
ForumPost post = ForumPost(PostID);
if (post.RootPost != null)
{
Root = ForumPost(post.RootPost.ForumPostID);
}
else
Root = post;
}

it works too. But problem is in speed. I not need in RootPost all those includes. So, I should to create one more method like:

private ForumPost ForumPostIncludes1(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
.Include("ChildPosts")
where i.ForumPostID == ForumPostID
select i).First();
}

then ForumPostIncludes2, ForumPostIncludes3 etc... second way - redesign RootPost with LINQ expr, not with call another method. But in this way difficulties to change DB. third way? How to do it correctly?