How do I create an easily accessible directory outside of /Users/?
I changed my Dropbox directory to /links/Dropbox with no problems the Dropbox app created a subdirectory Dropbox there. I created this directory with New Folder from the Finder

links mark$ ls -l
total 0
drwxr-xr-x   3 mark      admin  102 25 May 17:18 Dropbox
drwxrwxrwx   3 mark      admin  102 30 Nov 20:10 V
drwxr-xr-x   5 mark      admin  170 30 Nov 20:32 VirtualMachines


and

links mark$ ls -l Dropbox/
total 0
drwx------@ 24 mark  staff  816 25 May 17:18 Dropbox