Little bit OT but SEIV related

[Suicide Junkie]

Well, the colony module makes up two thirds of the ship... and you want to land all of that in a month or less.
You would want the big ship engines to slow the descent (even harder than navigating interplanetary space), notwithstanding atmosphere dependent landing techniques like parachutes. All that's left is the Bridge/LS/CQ.
You'd still be using those three items to survive on the surface as your technicians deploy the colony module and set up the domes so you can breathe.

I can imagine an independent colony module which can simply be launched into a system, land and deploy by itself. However it would be pretty wasteful to have the skeletal remainder of the ship return to load another module...
Building a new colony ship is only very slightly harder than building just the module.

A ship which could carry multiple colony modules, and perhaps even be equipped with enough to colonize an entire starsystem simultaneously might make use of the independent modules, but it would be a horribly large cost for one ship, and it would be more vulnerable than an equivalent fleet.

PS: although SE4 would allow you to quickly and easily repair the module, it is totally unrealistic. Its the same as retrofitting a bunch of bases to form a ringworld in two turns. Except without any cost.

Or like the colony ships that left Europe for the New World, they could return home for redepoyment.

IMO, this is more like having a population transport being able to colonize a breathable, home-surface type world by dropping people on it.
If the environment encourages instant death, say humans in an oxy gas giant (falling), or humans on a vaccuum rock world, this would not be possible.