is there a new posts button or since last visit button so that i can view active topics?

Go back to the main forum page and scroll to the bottom. In the 'Forum Statistics' section you'll see a small box which will let you 'View the ___ most recent posts of this forum.'

I don't think so.  I've been on some forums that track what you've opened.  The next time you go to a thread, it will open on the next post since you visited.

Some have a button to send you to the first unread post, but those don't seem to work, at least not on a couple of other forums that I frequent, infrequently.

What Stasher1 said. You can select the most recent 10, 20, 30, etc. posts.  I find it hard to use because every post is out of context of the thread.  But give it a whirl and see if it suits your style.