According to D K Woods :
How difficult would a resurfacing project like this be? I'm new to
flooring AND to concrete.

I've fortunately not had to do anything like this, but I've heard some
of the stories...

Perhaps the first thing you need to do is identify how much of a job
this will be to do _right_, this is how you find out what magnitude
of problem you're dealing with.

"Solutions" range all the way from just bridging an occasional dip
with subflooring (ie: plywood sheet), all the way to laying and
leveling a few inches of new concrete over the whole floor.

[Both my family and my inlaws have been thru the "pour a new floor"
version. They needed it...]

Even _with_ seeing your floor, I'd probably not be a good source
for recommending the right solution. How widespread is the problem?
Is the floor generally flat with occasional dips/ripples, or,
completely unflat (ie: different slopes thruout the floor)?

This is where I think it'd be a good idea to call in several
professionals, each with different "solutions styles", get estimates,
and find the best fit.

You're probably looking at several days for curing. Likely weeks
(or even months) before covering with wood flooring over fresh concrete.

The fumes are unlikely to be a big deal (concrete "fumes" are just water
evaporation...), as long as you have active ventilation.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.