Already in 2011 NASA Ames Research Center proposed a Mars mission called Red Dragon that would use a Falcon Heavy.
A SpaceX 2015 estimation was 2,000-4,000 kg to the surface of Mars with a soft retropopulsive landing of a variant of the Dragon capsule.
So a small bulldozer could be used as a payload instead.
A bulldozer is a continuous tracked tractor equipped with a substantial metal plate (blade) used to push large quantities of soil or rubble. It could be equipped at the rear with a jackhammer to break up very hard earth or rock.
On Mars a robotic bulldozer could break up sedimentary rock and very hard soil with the jackhammer and then remove it with the blade.
In this way layer by layer of the subsurface could be investigated by a present rover, and with a much larger area then that of a hole drilled by a rover alone.
Of course the bulldozer would need much more energy storage capacity, more like that of an electric sports car, to do it's job. But it needs only to work for less than an hour a day because the present rover will have enough new material to investigate for the rest of the day.
So if the bulldozer has a 10 kW engine, it needs not more than 10 kWh energy a day.
A RTG that has 500 W power can deliver 12 kWh each day to the storage batteries.
So because much more information about the historic past of Mars can be obtained by breaking up and removing the subsurface, why not use the assistance of a bulldozer ?
It is believed that large quantities of water and carbon dioxide ices remain frozen within the regolith in the equatorial parts of Mars. An intelligent bulldozer could prove this believe to be true !