1. Go straight two blocks and turn left.

2. Go straight for two blocks and turn left.
[Are both okay? Which one is the better of the two?]

Go straight two blocks and

Both instructions are correct and will result in reaching the destination. However, the better of the two depends on the specific context and surroundings. If there are specific landmarks or points of reference that would make it easier to navigate using one direction over the other, then that would be the better choice. Additionally, considering factors like traffic, road conditions, or other obstacles may also affect the decision. It's best to assess the situation and choose the option that seems more convenient and efficient at the time.

Both instructions are technically correct and will lead you to the same destination. However, the second instruction seems to provide more clarity by specifying that you should go straight for two blocks before turning left. This additional detail can help avoid any confusion and ensure that you follow the directions accurately.

In general, when providing directions, it is often better to be as specific and clear as possible. This helps the listener or reader to easily understand and follow the instructions without any ambiguity.

Both are fine. I'd probably use the first one more often, but that's just me. Neither is better than the other.