Consider waging a guerrilla war (many examples throughout history where a small guerrilla force has beat back a superpower) and fighting for your home vs. a pilgrimage to a mythical planet. In hindsight the choice might be wrong, but in reality the first choice is the more rational option that most people will take and many have previously succeeded in. Thus, you have to judge her based on that. And Adama's quote seems to say that her tactics were flawless in waging that strategy.
How many Cylon basestars did the Pegasus knock out? How many more could it hope to knock out before it ran out of luck, or just lost enough people to not be able to keep on fighting?
Unless she could hope to wipe out every Cylon with her single battlestar before her luck ran out, she didn't have a strategy any more than Butch and Sundance did in the final scenes. At best, she was just going out fighting, taking as many of 'Them' with her before she went.
That's a tactic. It works strategically if you're buying time for the other units to regroup and fight back once you've made your heroic sacrifice. But if you're all that's left (or think you are), then...
Should Janeway have set down on the first habitable planet? You could argue she should have. The odds were long yes, but some things are worth fighting for like home. Remember Adama would have fought as well. In the context of the universe, the odds might not have been as bleak as you portray. If Cain were still alive, commanding both the Pegasus and Galactica engaging in a guerrilla war, I don't think the odds are as bleak as you portray as displayed by their one successful collaboration with her in command of both. Adama acknowledged her tactics engaging in this type of warfare were pretty flawless. They might have run into other Battlestars that survived. Too much to hope for? You could argue a pilgrimage to a mythical planet was also.
The same things you guys are saying were said about other guerrilla warriors throughout history against mighty superpowers but many succeeded in what were considered long odds. Never count out a guerrilla force willing to fight and die for their homes.