Thanks for the kind comments. I am not aware of way cars, always something new to learn. That Burlington ice reefer came with my Lionel Icing Station accessory. It would not take much to made a reefer by adding a hopper into the top into a milk car or box car. The reefer is part of my operating car train that is always on the layout and has a milk car, cattle car, barrel unloading car, log dumping car to dump on to the Lionel Sawmill and a gondola or coal car to accept canisters from the Gantry crane or coal form the mine car loader. For now one reefer is good and I am not tied down to any railroad line. I am glad you and your grandson enjoyed the ATSF caboose.
Yes this topic, on post 9 on page 1, has details on my $10 turntable and roundhouse and most everything on my layout including lots of my homemade cars and accessories. There is a table of contents on page 1 also to allow anyone including me to find where each subject is.
I could have bought all the things I homemade, (eBay has most if you can out bid and pay postage for them) but I really like to make many of them and have been a model builder since childhood and found I enjoy making them more than operating or running them. The turntable is a good example of having fun planning it and building it for next to nothing 43 years ago. They are very simple unless you need an automatic indexing one.