There are really two votes here.
- Voting on which proposal which actually be voted on. There might be several proposals, but only one proposal can win per proposal period.
- After a proposal has been selected there are two votes on the winning proposal. The first vote during the exploration period, and the second vote during the promotion period.
For more details on this, if you haven't already read this Medium article on the amendment process, you should. It is a very informative read.
Also to see the state of the current proposal look here on tzscan.io
To your question though, there is no official way to know the intentions of the bakers. Larger bakers will likely post on their website which proposal they will vote for and if they will vote yay, nay or pass. This is not a guarantee, but most responsible bakers would have no interest or incentive to lie about they way they will vote (at least not yet anyway, the proposals haven't been contentious enough yet).
Even if a baker does not post their intentions on their website, or if you want further confirmation on what they will do, you can see which proposal they have voted on during the proposal period. After the first period follows the exploration vote period. You can see how the baker voted during this period as well. If you don't like what you're seeing, you can choose to move your XTZ to a different baker.
But do note, it's still possible for a baker to change their mind after the exploration vote period. And this isn't necessarily dishonest in any way. Let's say after the exploration period, the proposal goes into the testing period and the testing of it turns out to be a total disaster for one reason or another, then a baker that at first voted 'yay', may very well, in good conscience change their vote to 'nay'.
To see how a baker has voted through the various periods, look here using the baker's tz1 address.