Thank all for replies.  I did not know what I was getting into with this era - any scale.  Late 1800's in HO had much more options off the shelf.

But I won't quit just because it's harder ....

I will be cutting down a used 40' coal car in the next week or so to try my hand at modifying it to 26' - a first for me.  One thing I read somewhere is that a cool part of model RR is that if you do something and it doesn't turn out right - just tear it up and try again ..... wonder how many used cars I will go through until I get it right!

This is my first N and I bought several used cars and an 0-6-0
for perspective.  My setting is mid 1800s, Appalachia West Virginia.

For the first new purchase I settled on a 4-4-0 engine that
I bought from Bachman.  The actual details are not what I am looking for - but will do
for the early set up and track work.

Here's the catch I didn't see coming.  The smaller boiler and lower lay
of the older style 4-4-0 doesn't look right with the railcars.  Even
though the longest car is 40' they look too high and wide.  I assume they
are modeled on late 1800 to early 1900 stock.

With my old HO this is not so noticeable.

Is there an identifier for smaller cars?  Who carries smaller size
cars?  Seems there should be a code or size for older era railcars.  Does
anyone know of a source I can follow to learn more?

Also - does/did anyone make an N 2-2-2 from the early 1800s?

Finally, for all scales, where can someone go for loco/rollingstock modification information or kits?