Even if we didn't have to I would still want to try, I think exploration is at the heart of the human
experience. Exploring ideas is a good start.
As far as terraforming equipment, there
should be ways to mine resources on a longer time scale I would think and build equipment there on site, but I wonder if there may be a possible low tech approach. Obviously not so much in getting there because you need some pretty high-tech gadgetry to get there. Maybe like a small scale approach of tiny ecosystem in jar not much more advanced than what Toby Hemingway talks about in
Gaia's Garden I think is where I heard it. You take a gallon jar, scoop up some
pond scum, some soil out of the woods, and I can't remember what else, but you close it up and set it in the Sun and a tiny ecosystem will form. Scale this idea up a bit and I think it might be possible to have something to build on.
A planet like mars has some atmosphere it's just really toxic and if you look at really thick rainforests they almost create their own atmosphere at least to some degree. If you could scale up the ecosystem in a jar idea and build on it and build on it over time maybe it could eventually become stable enough to poke a tiny hole through to the outside environment. Then maybe you could gradually make this hole bigger over time and the shake and bake ecosystem could start to nibble away at the toxicity and release some of it's developing atmosphere out into the planet.
Obviously this would be a very very long time scale. So I suppose the idea would be to set up an expandable
greenhouse that is tight to the outside air but not so much to the
native ground. Take organic material there to start the processes and build on top of what's there. Bring in bacterias and funguses and just a really mixed bag of weeds.
There would plenty of light available but water would definitely be a problem unless there is source on the planet yet unfound. Taking Earth's water there might not be that practical or at all wise but maybe an icy comet happens to be in the neighborhood or a way to generate it locally.
I suppose the ecosystem in a jar idea would actually be more practical for long term deep space travel than it would for terraforming. Might work for both, but the travel idea is at least easier to chew on for now.