Help with huge room layout.

So the train I have so far is a Lionel Norfolk Southern in "O Gauge" with the Lionchief control.
I read that O-27 will run on regular O, but not the other way around, so I'd rather keep the track at regular O so I can run both.
The box mentions "O 36 track", so that's regular O from what I can tell. Am I wrong?

 

Yep, a 2% grade rises at the rate of 2 units of rise per 100 units of track length. Inches, feet, meters; doesn't matter, as long as rise and run are in the same units.

 

"O-36" is for a loop diameter of 36 inches, and therefore a track curve radius of 18 inches (all dimensions are to track centerline).

 

So is that standard O gauge then?
Is it safe to use that curve or best to use something bigger?

 

O gauge in the distance between the rails, but different types of equipment are designed to negotiate sharper curves than others. I'm not sure what constitutes standard O gauge equipment, but its recommended minimum radius is 72", per https://www.thesprucecrafts.com/minimum-curve-radius-model-trains-2382285

I model in N scale...

 

In general you need at least
100 inches to rise 4 inches, (4% grade),
but
200 inches to rise 4 inches, (2% grade)
would be much better.
How big is the table?
Basic principles:
Keep your arm stretching distance to 2', (how far you have to reach if you need to get at something)
Build a frame and put insulation foam shhets on it.
Plan on going DCC from the start.

As for books? I don't know what is currently available. For now I suggest you keep it simple.
Start with putting down:
A loop of track
A passing track
A couple of spurs for industry
A two or three track yard.
Use sectional track on a foam base.

Note: This is over simplyfied. I have never worked in HO or O scales so there are a lot of other factors I'm sure.