Any of you like Star Wars? Han Solo said:
If we don't calculate exactly we could fly right through star and cause a super-nova!
If a mere space-ship can fly through a star at hyperspeed, it makes sense to suppose a
time machine could fly through Lavos' shell at warp speed! Keep in mind that the Epoch broke. Also, 0 AD is the founding of Guardia. Therefore, it stand to reason that 1000 AD is about 1700 AD in real life, and 2300 AD is about 3000 AD. I would say they'd have quite advanced metals and power sources. Mainly things we couldn't comprehend. Who's to say that an unfinished Epoch couldn't fly through time with NO living passengers. He might not have finished the life-support systems.
The only problem with the dreamstone theory is that it was previously stated that the Dreamstone would draw out the rider's hopes and dreams. However, the Epoch did followed Crono & co. with no riders. Also would that make the Epoch effectively
evil while Dalton was riding it? Who was riding the Epoch in the battle with Dalton anyway. Therefore, it stands to reason that there was another powersource.