And to reach that goal, the agency should have a focused, coherent, and incremental plan for getting us there. Considering NASA's small budget, one main project at a time is all they should attempt. Trying to do everything and go everywhere at the same time will only leave them where they are now....nowhere.

Here's my list of objectives for NASA:

2000-2010: SST, CATS or whatever you want to call it.
The main hurdle for space missions is the cost of getting "out there". Once that cost has been greatly reduced then private parties can build their own probes to explore their favorite pet destination.

2011-2020: Orbital Space Port:
Space at such an outpost could be leased to groups such as Artemis or others so that they can assemble their craft for various destinations (i.e. Moon, Mars or beyond)

2021-2030: Luner transport + base

2031-2040: Mars transport + base

2041-2050: Design & build a robust inner solar system transport.

2051-2060: start mining NEO + asteroid belt objects

2061-2070: Manned exploration of outer solar system using large explorer ships

2071-2080: First robotic interstellar probes

2081-2100: Begin building large space habitats with the expanding space infrastructure

2100+" AD ASTRA!

This basic infrastructure can be built by NASA and leased by the private sector as a jumping off point for their own projects. Once cheap access to space has been realized, then private entities can plan their own missions to where ever.