Flying from California on a transPacific flight would require a velocity not much less than orbital velocity. When I tracked Soviet ICBM trajectories for a given range, I saw that their peak velocity was only slightly less than orbital velocity, with the biggest difference being not velocity but trajectory.

SpaceShipOne (and Two) are designed to go high, not particularily fast. SS1's peak velocity was about Mach 3.2. In theory, it could go faster if it flew a more ballistic trajectory but then it would get a lot hotter, requiring much more elaborate thermal protection. Even then, I doubt it's ballistic range would be more than a couple hundred miles. Look at the V-2, Redstone, and Scud missiles and compare their speeds/ranges with SS1/SS2. Those missiles flew faster but only have ranges of 200-400 miles, depending on warhead mass.