Different Twist on Redirect After Login?

I’ve read many forum posts about different methods of changing the page to which users are redirected after login (instead of the dashboard). I am one of those who has users who are confused by the dashboard.

Some say change wp-login.php while others recommend using a plugin. One suggested modifying the login link in the theme files, but I found no such link in my theme files. I really want to avoid changing a core file that will be overwritten during updates, but even if I were willing to do so, I still have a snag:

If a user goes directly to my base wordpress URL (www.mydomain.com/wordpress-dir/), I want them to go to the blog’s main page (the latest blog post), NOT the dashboard. I know how to accomplish this by a couple methods. However, if a user gets to the login page by clicking on a direct link to a specific post in an email notification, I want them to proceed to THAT page after login. It seems logical and reasonable to me, but I haven’t found any method that accommodates this.

Can anyone help?

I should say I am running a members only (login only) blog, hosted on a domain and host of my choice. Everyone must be registered by me (the admin) and everyone must login before accessing any page on the site.

I hope there is some solution. If a solution exists, but requires SOME core file changing, I would be willing to do it, knowing that it would be overwritten at every update.

Hopeful…
RC