Except for awful VFR+GPS chart from Jeppesen (there are no lakes depicted, etc.) and pure boredom with flat landscape it's actually pretty easy provided you know how to do DR properly or you navigate by other means. Be sure to have all the frequencies that you think you might need written down, since ATC tends to mix the numbers - the accent doesn't help, truth be told.
And if you actually read the AIP, there is nothing that even remotely suggest you would need S-mode transponder for VFR flights, neither does Jeppesen VFR Text for Hungary.