A few years ago got the C64TPC which connects the C64 to the PC w/ a serial cable. I don't think he makes them anymore but I remember it being cheap and it worked without issue.
Then I picked up the 1541 ultimate II cart for getting files from the PC to the c64. Although it was a bit pricey I totally love it and have no regrets.
I also remember getting a cable that connected the 1541 to the PC's parallel port, it was really cheap but never got it to work at the time.
Although I haven't tried it, I would recommend the sd card reader, it will make it so much easier.