dropbear will automatically run at startup, if you have a dropbear folder with a key in it. Instructions on that are
here.
As for cricket, that sounds very much like what was happening with many carriers before ppp auth was working. Connects, get an ip address, but won't actually transfer any data. I don't know if that means it's got the wrong authentication information, or if it's not dealing correctly with the proxy, or something else. I never really understood exactly what changed with the authentication to make it work.