FTP (or similar) over serial port of an embedded linux system

Maybe this question should be posted in a linux development group,  
however the use of a serial port is more typical in an embedded  
environment, so I try to post here.

I have an embedded Linux box (based on a Raspberry) with a serial port  
converted to a USB port through a UART-USB transceiver from Microchip.  
This USB port is seen as a COM port under Windows OS.

I need to do simple operations on the filesystem through the serial  
port, mainly:
- list files in a directory
- download files
- upload files
- remove files

The user on the Windows PC should launch a simple script (it will be  
written in Python) that make all the operations in sequence.

Do you know of some technology/protocol that could be used in a simple way?

I have two ideas, maybe there's another one that is better.

The first is to configure a PPP over serial line and use classic FTP  
server for filesystem operations. However this solution implies that the  
user should configure the PPP link, but she will not have so much knowledge.

The second is to run the classical console on the serial port, with  
login and prompt. The python script should type/send commands at the  
prompt (ls, rm, ...). The download could be done with hexdump command  
(the python script could convert to binary again).
The upload should be done with echo command, writing a ASCII hex file  
and launching a simple script to convert from ASCII to binary on the  
embedded Linux.

Do you have other better solutions?