Pixie/Highway is capable of scoring wickedly fast, thanks to a synergy between Forest + Earth Boons, Highway and the presence of Goat to speed things up.
The Build
1. Open Pixie/Pixie, unless you have a 5/2. If you do, open Highway/Pixie.
2. Focus on thinning down with Goat. No need to get any other trashing, especially no need to waste a Pixie to pop Flame's Gift.
3. If you can hit $5 on the way, you may go out of your way to do so. This means you can pop a Pixie in order to guarantee a $5. Getting a Highway early is crucial.
4. Buy Pixies on off turns in the mean time. Pop one every time you can activate Earth’s Gift or Forest’s Gift, if you know you can net gain a Pixie. If you have Highway in play, these two boons become even stronger.
5. Try to prioritize Pixies slightly as those are your gains, but find a balance between gaining Highways and Pixies.
6. Get about 5 Highways at a minimum. While 4 is enough to activate Province gains with Earth, getting Forest’s Gift to work for you is crucial as well, and sometimes Highways will hide.
7. It probably goes without saying, but always play Highway before you play Pixie.
8. You should be able to end the game in about 11-12 turns, with 5+ Provinces in your deck.
Note that you can probably do even faster builds with the inclusion of other cards within a Kingdom. This deck is only the launching point. Be creative and keep your eyes open.