It's pretty easy, I must admit. Those who come to Taco Twosday will recognize the starting location, but that won't necessarily give you an advantage.
You can get the final coordinates by visiting the listed waypoint using the middle 5 of the 7 numerals that are stacked vertically as your certitude code. If you're lucky, you can park right there and get the answer without leaving your cachemobile. The final is close enough to walk to, but you may choose to drive. Watch for Muggles at the final.
You can validate your puzzle solution with certitude.