On right track?

Basement space. 15' along wall. in middle sticking out 8' x 4' Along sides a passing with parking yard. along other direction a loop with small branch. Center area industry of some kind.
Basically a big T that will create some type of work to be done and allow switching with the outer areas.
first build and just need to get going. Doing ho with dcc.

overally ambitious or OK for first timer?
Also- What type of space between tracks for a yard?
How do I measure code on track already in possession? Not layed