It would require very large RTGs to do the work you are describing.

What a practical Mars base needs is a nuclear reactor. That should be one of the first things landed (if not the first) in any serious attempt at a permanent base.

(These people have some great case-studies on terrestrial fabrication. )
https://shotcrete.org/

There are other methods to support a craft in unknown soil properties. Some are discussed in the first landing on the moon because they were unsure that it would be like “powdered cement” on the surface.
On Mars they will need adjustable landing struts to keep the craft upright, this may include a length of spring steel rod that pushes into the ground using the weight of the craft. And/or stabilizers that fold outward that are used to stabilize cranes.

If the evidence for water has long evaporated, or is too deep from the surface for convenient use, they’re are alternative sites that are certain to have what they need.
The polar ice is on the surface, and is only 50° colder then what is already far too cold. An RTG on a rover can melt a dust free habitable tunnel complex into the ice ready for air locks and carbon insulation in a stable (hopefully) radiation free artificial environment requiring minimal construction. Ancient water, methane, nitrogen, as well as as an abundance of solid carbon dioxide will be available upon colonization. The RTG can also be used in the separation process to melt carbon dioxide ice in a pressure container, into a high-pressure liquid that can be used to generate power in a two-stage process. High pressure liquid to high-pressure gas in the first stage then high-pressure gas turning a second turbine into low pressure as it’s vented outside creating far more power then the RTG can ever make as an electrical device. This is sustainable as the vented gases will refreeze and can be recycled endlessly. Life on Mars will need an abundance of power, this is the best available until nuclear power plants can be constructed and brought online. (Hopefully Russia will allow the purchase of some of their nuclear submarines for this purpose)
Once a staging area has been secured with manufacturing process enabled probably by 3-D printing, the rest of the planet can be surveyed, sampled, underground tunnels mapped and cleared of debris and reinforced by construction materials supplied by the polar intermediate materials colony. Baby steps…

Maybe something that can actually excavate.

I wonder if a private company can use an RTG?

Mars is one freaky-deekey place.

DannyG: How is the metal grid you describe shipped? If as a roll it would make implementation relatively easy. You would basically put the roll on the ground and let it unroll.

If shipped as sections that are clipped together it might pack easier, but assembling the sections on the ground would likely require humans.

Jay: SpaceX is quite happy to work with NASA and the scientist community on its Mars project. Remember, NASA is likely its biggest customer. Musk might want to go to Mars, but he also always focuses on how he can sell the product.

In the end, I strongly believe it will be with Starship/Super Heavy that NASA’s big manned missions to the planets will be achieved. It just will take some time for this to unroll.

that being said….

Pink Floyd –
Set The Controls For The Heart Of The Sun / Mars Direct
https://youtu.be/a9ntxCcjVjE
9:47

Who builds the first pads (human or robot) and out of what are big questions. Hauling concrete to Mars is obviously not feasible. I would guess a robotic “Bobcat” could do a basic clearing and leveling, followed by the application of a chemical binder compound to lock down the surface materials.

Once humans are landed in sufficient numbers, serious pads can be built, along with some infrastructure for moving ships to and from them, so multiple ships can use a pad.