How do you convert to Hinduism to get married in India?

You can't really. One must be born a Hindu - there is no such thing as "conversion." The traditional view, would hold a foreigner as having no caste (an "untouchable" for all intents), white or whatever, and would not be a Hindu even if married to one. Thus, if you went to India, chances are you wouldn't be allowed in many temples by the priests.

Of course, you have a lot of American Hindus saying you can and you'll have no problem in an American Hindu temple, but trust me it would be a very different story if you visited India.

Hinduism not a religion, it is called as religious tradition for a reason! There is no one called Hindu! Hindu is name given to People of India by British as India had great River Sindhu and later the Religious tradition of India was called as Hinduism by foreigners. But truly, there is nothing called Hinduism or Hindu. The name Hindus/Hinduism never mentioned in any sacred texts of Hinduism. It should be actually called as Advaita Vedanta (Universal Religion). If you can attain Vedic knowledge, You are a Hindu/Advaita Vedantic. Just read Bhagavad Git For Modern Times By Swami Sadashiva Tirtha which summarizes some important aspects of Vedic Knowledge. There is no religion convert rituals or anything, God is already within you, you just need to realize it and God doesn't intend to create religions, it was humans who did. But if you can understand the Hinduism (Vedic Knowledge, Advaita Vedanta) you will know answers to many of your questions.