Hi Purplecrow, 
I have been a practitioner of Kriya under the guidance of Yogiraj Gurunath Siddhanath of the Hamsa Yoga Sangh for about 15 years.  Although it's been a while since I reread Autobiography of a Yogi, many of the experiences described in the book are shared by me and my fellow disciples such as seeing of the third eye.  Kriya is known to us as the lightening path and is not an easy one by any means.  There is a lot of rapid karmic purging and it can get quite arduous at times.  Kriya yoga involves the direct arousing of the kundalini energy anything in the higher bodies which gets in the way is thrown out.  Euphoric states are experienced as well.  Basically it's a path based on the validation of spiritual truths through direct experience  rather than reading about them.  Like they say, " You can write volumes on how an orange tastes, but it's not the same as the actual experience of eating one".

And as a reply to Slacker Yogi, the lineage of Sri Yukteswar is very much alive.  Hariharanandaji was Sri Yukteswar's last direct disciple, I beleive, but he was succeded by several high yogis (Gurunath being one of them).  Also Gurunath states that the last direct disciple of Babaji was Lahiri Mahasay, and that there are no direct disciples living in the public.

peace,
Nivrutti

By no direct disciples living in the public he means that Babaji has no discples who are activiely teaching in the public.  It is said that Babaji moves with an entourage of yogis who stay in the Himalayas,  unseen or invisible from anyone.  As far as the fact that Lahiri Mahasay was the last disciple, come to think of it, I may have to double check.  I thought that Neem Karoli Baba was his disciple. :)

In answer to those interested in Kriya yoga see the book entitled "Autobiography of a Yogi" by Paramahansa Yogananda.  Paramahansa Yogananda was/is an Indian Saint who reintroduced this ancient yoga to mankind in the first half of the 20th Century.  It is all detailed in his book.  Also, you can google: Self-Realization Fellowship or go to:  www.crystalclarity.com or www.ananda.org

Informative post for me because I like yoga exercise.Thanks