It's all relative.

Cavemen had no understanding of Space, so telling them there's a big unexplored continent on the other side of the world would have sounded just as alien or crazy. And it still took them thousands of years to finally build ships and navigate the oceans before successfully touching down in America or the coasts of South Africa.

Based on today's science, going to Mars is obviously a bigger challenge. But in 500+ years, I expect the gap to shrink and it would be no more harder than riding the Bus to a different part of town.