If you missed those three episodes, you're probably fine. I don't think anything of particular importance happens in them (there is an alien in "Throne for a Loss" that pops up again in Season 2, but it's still not overly important).
Farscape has a lot of standalone episodes in the first season. They're not all terribly important to the plot, but you do learn things about all the characters. Frankly, "Back and Back and Back to the Future" is one of my least favorite episodes of the entire series. It's no big loss if you don't watch it.
In Season 1, the episodes that I would absolutely watch are:
PK Tech Girl
DNA Mad Scientist
They've Got a Secret
A Human Reaction
A Bug's Life
Nerve/The Hidden Memory (two-parter)