[Space/Spaceships] Getting the velocity/Delta V I want with the tech I want

[David Johnston2]

Originally Posted by scc

OK, I'm working on a so far hard Sci-fi setting and I've got two planets that are 400 AU apart, +/- 44 AU. Now according to my math that means that at a velocity of ~300 mps it will take a ship 4 years to move between the two planets.

My problem is that I want there to be somewhat regular trade between them (In fact one's supposed to be settled from the other).

The logical thing to do is to either dispense with the apes in cans or use FTL.