For what it's worth, here's what I do:
1st, go to Users Folder and note the exact name of the primary user (every system we build gets "Admin" as initial user but most others tend to use their name if they setup the system initially). This name will be the username and so the password that user uses for that will be your password.
Keep in mind this assumes that you have shared at least one folder on the target system (basic share might be the Downloads folder shared with "Everyone" with Read & Write priveledges). Such a share will only be accessible if the account username and password are known and used...
Then, when you "Browse" via Hamachi to that system, you will be able to login and access, even map that shared drive on your system with a letter of your choosing as long as you are connected to Hamachi appropriately...
Hopes this helps you and others using the LAN over WAN abilitiy of Hamachi...