The only firm in-canon mention I can find is Yoda's statement to Bail Organa near the end of the Revenge of the Sith film:
Into exile I must go. Failed, I have.
It makes sense that he would feel this way, as he tried to confront Darth Sidious, but was unable to defeat him. Presumably, he saw no way to defeat the empowered Sith anytime soon.
Personality-wise, Yoda was not an impulsive Jedi, nor was he a front-line 'soldier' (despite him being a Swordmaster) - he was a wise teacher. Thus, with the Skywalker twins being 'spirited' away into hiding, he could see that their best chance was to wait.
The prophecy of the Chosen One was seen by many as being Anakin Skywalker - and in the end, of course, it was. But when he fell to the dark side to become Darth Vader, no doubt Yoda questioned it, especially when he was becoming less believing in the possibility of redemption for fallen Jedi. So, while there were certainly other Force-sensitives out there, it seems likely that he would wait for the time when the children of Anakin, themselves highly likely to be strong in the Force, were able to take a role in the opposition.
When Yoda went into exile, there is no doubt that he knew this battle was not to be won by strength against strength. And indeed it was not. The new Galactic Empire controlled hundreds of star systems, and had a new massive Army and Navy. The new Emperor Palpatine had enough control and power to squash less powerful Force users, and as showed later, the ability to ferret them out. Yoda and Obi-Wan understood that this was tomorrow's battle, not today's.
And so in the end, Yoda's work proved vital. He helped to train a great Jedi in Luke Skywalker, and that was one of the key movements that brought down the Empire. In letting Leia work through different channels, she was able to be an instrumental member of the Alliance, and was again, very instrumental in bringing down the Empire. So while we can't say for certain everything worked out exactly as Yoda planned, 'history' vindicates his choices. And I'm sure if you were to ask him what exactly his plans were after Episode III, he would probably respond...
Difficult to see. Always in motion is the future.