I don't know what you mean about "junk" science. Hovind tended to speak to young people in most of his seminars, so his lectures and debates were purposely very simple, designed so most anyone could understand.
But his points were good and valid as this college professor from Arkansas admitted;
http://www.youtube.com/watch?v=mtt5dFyIvy8#t=138
As far as Hovind and his tax troubles, I don't know much, but I am sure it was related to his ministry. He did preach the gospel in addition to his seminars on evolution.
I sincerely believe Hovind was persecuted because he went to universities all over and refuted evolution. He made lot of enemies in high places.