Here is my trouble shooting so far.
Full NVRAM erase. Have been able to reproduce it on the following builds.
Tomato Firmware v1.28.9054 MIPSR2-beta K26 USB Ext
Tomato Firmware v1.28.20111009 MIPSR2-beta-tomato-RT-GIT K26 USB Ext
I tried to test tomato-K26USB-1.28.9055MIPSR2-git-13042011-gcc-4.4.6-Ext but doing that lost the web gui and I used the ASUS utility to go back to 1.28.9054
When setting up remote access I have tried
HTTPS on 8080 and 443
HTTP on 8080
I have also tried to setup a local route on my machine to go to the LAN ip address of the RT-N16 using it's public IP as the gateway and that also did not work.
Real easy to reproduce
Do a full nvram erase (optional)
Turn on Remote access
Switch from Gateway to Router
Remote should no longer work.
I did a search and I did not see it reported or maybe it's something I am not understanding that routing mode introduces.
Thanks for any help you can provide.