If you assume that terraforming will take as long as it certainly will take (to begin, and then to complete), then you also have to assume that our technology will advance a LOT between now and then.

Maybe we will be able to formulate and create a rad-blocking atmosphere.

Maybe we will be able to formulate simple light-weight radiation screens.

Maybe we will be able to design a rad-tolerant biosphere with rad-tolerant humans.

Maybe we can provide mars with a LaGrange (which point is the Solward one?) orbiting rad deflector/shield.

Maybe we will be able to supply Mars with a magnetic field.

Until then, all you need is a freaking shovel!