just wondering is there anything like the /g, /s, /p, /1 commands for typing in different channels?

Or do you have to use the drop down menu each time you want to type in another channel?

They're pretty standard slash commands:

/s - Local
/f - Fleet
/p - Team (aka Party)
/zone - Zone
/r - Reply

You forgot /c <channelname> for any custom chatchannel you joined.

edit: to be precise if you want to talk in the tts chatchannel you would need to type sth like: /c tts Hello world!