In HO, a 27" deep closet will not be sufficient to completely contain a turn into staging for typical equipment, as the radius would be around 12" once allowing for the width of the track and clearances. Fine in N scale, of course.
Some thoughts on the Free Haven Terminal Layout from my blog. There are a few things that one might wish to change for realism and better operation – and better access to staging. But it’s a great starting point.
A google search leads to an unofficial archive of that site – use caution – for now there seem to be no malicious links on that page, but no guarantees. http://www.oocities.org/trainternet/Fhht_us.htm
As I said, this concept is neat, but I would change a number of things in the actual design. So there’s no ideal spot that I would suggest to put a car float as-is without adjustments to the rest of the layout. Redesigning the layout to fix all the details would take more time than I have to spend, unfortunately.
If you were keeping the layout otherwise the same, one could possibly revise the lead to the “Pier 3” Petroleum Products area to serve a car float instead, since at least one could shove cars directly out of the yard when switching the car float. But the better approach would be an overall redesign while keeping the same concept.