You can't plan so accurately for so many years ahead. What we do know is that times like now are good, or better times to buy and bull markets to sell. You can accumulate and between what you accumulate and the revaluation make partial sales but always keep some bitcoin because if it continues as we expect it will be the most valuable asset on the face of the earth, and I am not just referring to it in the economic sense.
If you run for an amount, then definitely you will be lured for more profits and hence you might miss the golden opportunity to sell the Bitcoins. Make a target for percentage of profit, like some have planned they will take 80% profit of their buying price. In this manner you can really make the desired amount and wont fall for profit traps. I know this opinion of mine, might vary from other people, but still its the best way to calculate and cash out the Bitcoins.