They would build a dedicated cargo section and fairing for this, all of that would be fairly straightforward to accommodate. I don’t know if SpaceX has acknowledged the idea but there was discussion of installing ’retro-rockets’ up in the fairing for the moon lander (to reduce exhaust blast on the regolith), could use the exact same technology.

If they were so inclined they cold even recover the helium from the tanks they are filling and use that to assist with pumping pressure.