Getting a Chinese phone number and bank account was surprisingly painless for me. You prepay around 20-30$ for a phone number at 1rmb/500mb and the account is a simple form.
Then if you have a nice bank account with fee free international withdraws you can convert money without fee by going to the atm, withdrawing, then depositing. All in all I’d say it takes about 2-3 hours, though I’ve heard ymmv depending on what bank branch you try to set up your account.