Since MyEtherWallet is an ERC-20 based wallet, you will be able to load all of your coins at once with one public address.
Find your MEW public address:
Take your address and go to ZenLedger, and click on "Import Transactions".
-Select Wallets from the middle navigation
-Select Desktop Wallets
-Select the Ethereum/Altcoins/ERC-20 selection from the dropdown
-Enter your MEW public address (not shown below, but you will have copied it out of your MEW so you can paste it here)
-Click "Add Wallet" and all of your transactions will be pulled into ZenLedger.
-You will want to go to "Next Step" when you are finished adding wallets to refresh your transactions.