If you send 100 tons a year, it would take 200 years to reach 20,000 tons.
I think that launching 200 tons in 2 to 4 years is feasible. We need to
think about what can be done with 200 tons. The machines will be smaller
than you'd like, but they should be functional.

You'll need more than one truck, because humans don't like to be stranded in
the middle of nowhere.
Trucks - 5 x 10 = 50 tons
Bulldozers - 2 x 5 = 10 tons
Cranes - 2 x 10 = 20 tons
Digging equipment
Solar cell manufacturing
Oxygen manufacturing
Iron or Aluminum manufacturing
Habitat equipment which includes a machine repair facility

I don't know what this adds up to.