how could I achieve 99.999% light speed, or the fastest possible (if I have infinite money and technology)?

You'll have to come up with some new technology first. At the moment no technology on Earth could accelerate something with as much mass a spacecraft to those velocities. We reach those velocities frequently in things like particle accelerators. But they're accelerating individual protons.... One idea is to use nuclear explosions as propulsion. This was actually tested back in the 60's using conventional explosions and works quite well. But you can only reach about 10% of the speed of light using that method. Never mind that even if you could come up with some propulsion technique capable of that it would require years of acceleration in order to reach that speed without crushing you. Then you'd need to spend at least that long slowing down also.

Very easy. At the moment you cross the event horizon (shwarschild radius) of a Black Hole, you are traveling AT the speed of light.

If you'd like to survive, since many Black holes have angular momentum and spin you could conceivable approach that Shwarzchild Radius very closely on a tangent and not fall in but glance off the black hole.

You can build another Hadron Collider like the one at Cern. It is accelerating protons to 99.9999991% the speed of light

You cannot accelerate large objects to this speed unless you harness the entire power output of the sun for a year, and you would probably kill any living creature you try to accelerate because of immense g forces of high acceleration necessary to reach these speeds.

Impossible. Remember that kinetic energy is proportional to the square of the velocity. If my math is correct, and ignoring relativistic effects that make the numbers even worse, traveling at this speed would require about 717,368,308 times as much energy as it takes to reach escape velocity. No amount of money or technology can ever overcome the laws of physics!

You would first build a time machine and find Captain Kirk or Scotty. They both know how a warp drive works.

Become Kenyan sonic.

somehow attach yourself to a bolt of lightening

hat does it mean by kenyan sonic

None knows.