Learning Japanese by yourself in the USA and not being exposed to the language (reading, writing, and speaking) on a daily basis would be a tedious and ongoing process imo where you will become frustrated and probably never get past the basics. How do you know you are speaking with the correct pronunciation, accent, and syntax if you do not have a native speaker there to correct and guide you and with whom you can converse with to ensure that you are learning correctly?
Without a native speaker on hand, you may be memorizing and speaking things completely wrong for which it will become ingrained in your brain and will be very difficult to overcome in the future.
You mentioned that you learned the first 10 hiragana in two days and hope to learn 10/day. If you lived in Japan you could probably memorize all the hiragana and katagana in a matter of a few days as you would be constantly exposed to it in your daily life on street signs, on TV, the trains, etc.
Therefore, my advice to you would be to wait until you have a competent, native teacher on hand to teach and guide you through the basics as, once you master the basics, especially pronunciation, and Japanese becomes a natural part of your life, you will more than likely never forget them.
Or, since you are in such a rush, you could go to Japan as an English teacher for a year or so, immerse yourself completely in the culture, and be proficient within that time. Also, if you have the funds, you could go on a study visa for the language and study 3-4 days/week at a language school. One year in Japan would probably be equal to three years learning in the US.
Good luck.