Most of the online trophies are simple enough, but reaching lvl 60 just seems too time consuming for a game which isn't all that great online. So I just done what is do-able on a few other games, which is rank up in a private match.
How to do it.
Go to MP, private match and choose RESCUE. Any map, but I recommend UNDERGROUND.
Go to match options: Time limit - 20 mins + medkits to retrieve - 20. Start match.
Now, if you start the match as Solarii, just run around farming all of the salvage boxes which will help you to upgrade your weapons and buy new characters, until the front of the ship opens (after about 5 mins) and press the red button to start the timer and end the round.
All the work is done as a Survivor. When you are on this team, all you have to do is run around collecting the medikits and returning them... EASY!!! you get lots of xp, you can also still collect the salvage boxes and if you drop the medikit (purposely) half way back to the return point, you get xp for the length of time you carried it.
Rinse and repeat. (could also do it with a friend and include kill challenges/trophies)
Obviously you will need to play online ranked matches to achieve some trophies, but I am using this method to reach lvl 60 so I can literally go into games trying to complete specific trophies.
Hope this helps someone, I just started doing it and am at lvl 16 after a couple of games
(Wouldn't be at all surprised if this is already known)