A good start and a good idea of fasting to lose weight and become healthy.
Your goal of losing weight to get to 170lbs when you hit true hunger is obviously arbitrary. You can expect to lose on average 1lb per day. During initial days of fasting the loss is rapid. Loss of weight simply diminishes in the latter part of a long fast. If you fast for thirty days you can expect a loss of 30lbs. You may lose more if you were active. Strenuous exercise is not recommended during a fast. You may walk for 15-20 minutes a day. You want your body to be able to expend its energy in healing.
Rest is recommended in fasting with nothing but water. Rest means physical, mental and physiological (all types of stimulation).
You may require more than one fast, if you make it to 30 days, if not more. I do not mean to discourage you but unrealistic goal setting is always disappointing at the end.
Also if you do a long fast, exercise is also recommended after proportionate period of eating.