I have a lvl 60 Series EV and the Tinkerers Lab mission pack. What would be the best lvl for exp farming with the lvls I have available?
My answer would be to try and find a friend to join and help you level. If you're after mana, the best levels are the MonsterFest levels, especially the underground cave level.
Otherwise, the Glitterhelm Caverns level on Insane is a good farm. You'll probably need another character to build towers to buff with your EV, but once you get a good build going, it'll be a great early game farm.