The Manuel Leon terminal at Madero is quite close by actually.
You can see in the attachment I included that you would end up at the 'Terminal de Omnibus de Retiro".
The Manuel Leon terminal is where I put the black X.
If one didn't have too much luggage, one could walk from the bus...
Why not an apartment rental since it's a few months?
It will be most likely less.
Lots of agencies out there.
A popular one I haven't heard any bad things about is: http://www.bytargentina.com/index.php
I've used them. They were excellent.
Any place where it's expensive & the locals have modest wages, they simply cram a whole bunch of people into one place.
That's seen in Thailand & BsAs, and I would imagine in higher cost US cities like SF, NYC, and LA.