>httrack <http://lcweb2.loc.gov/pnp/ppmsc>  -
>O "/home/history/websites/ppmsc"  -%v  -*.tif 
> The 'Parent Directory' structure it grabbed...

This is normal - either use 
<http://lcweb2.loc.gov/pnp/ppmsc/>
as starting URL, or use -* +lcweb2.loc.gov/pnp/ppmsc* as 
filter to avoid that.

> 1) I get all the tif files (at least till I kill it.)

There seem to be a problem if the last filter is placed at 
the end of the commandline - try:
httrack <http://lcweb2.loc.gov/pnp/ppmsc> -%v  -*.tif -
O "/home/history/websites/ppmsc"
I will fix that soon.