The key part of any realistic and expansive space program is going to have to be a large robust space station. It's clear that people are not going to be able to leave LEO in flimsy tin cans for more than a couple of days due to space radiation. The solution to this is protecting them with mass, and lots of it. That means building spacecraft with bulk to travel to the other planets. Ships too massive to be launched by a single rocket, and that are going to have to be assembled in orbit.

Capsules are fine for sending up supplies and personal to LEO, but not for much else. Leave manned interplanetary missions for real spacecraft.