Why a few thousand? Your Rousseau-ish political beliefs would play out far better with a few dozen.
A few thousand is still very much workable, as well as being able to sustain a genetically diverse (ie, no incest) population with a complex social system (ie, a lower percentage of people needs to be focused on survival).
GreatWyrmsGold, you are aware that you won't solve Earth's population problem with 2500 people on Mars? Because you said the reason to go on Mars was cheap real estates.
I'm aware, but it's still nice to have a "backup" for if and when humanity kills itself.
Also, why suddenly care about ecosystem?
...I hate people like this. The environment matters because
we matter, and if we screw up the biosphere we make it darn near impossible for us to survive, let alone maintain a halfway decent standard of living.
Just take over some shitty place, fuck the ecosystem and use your hydroponics. Still cheaper and safer than Mars because A) You don't need to worry about an athmosphere or cosmic ray and B) You don't need to go on Mars.
Or build a big, floating city and go in international water. Still cheaper than Mars.
The problem is, you're still subject to all Terran problems...and causing more, from the sounds of it. Another, less immediate problem is resource scarcity. Mars or Luna? Slap on your space suit and go make a mine (I know it's going to be a
bit harder than this, but it'll still be possible once you run out of metal or whatever). Floating city? Isolated island? No can do.
Again, there is no point to go on Mars. The Moon might be cool to serve as an orbital shipyard (To process minerals from asteroid and build the bots), but that's it.
Other than the "only" caveat on Luna, I actually agree. Unless we're expecting to
severely screw up Terra, Luna's far enough.
Going of your idea though: Buy a luxury cruise liner. Sail out into international waters with a few thousand people. Declare yourself the party king. Impractical as hell but still cheaper and more fun then mars.
This might be splitting hairs a little, but a
cruise ship has no chance of sustainable living for even a handful of people. I'm not sure if a couple thousand people could even
fit on a cruise ship.