Sections 7.3 and 7.4 of the data sheet have example code to read and write the EEPROM. Although they are in assembler, you can 'translate' then easily enough into C. To access the EEPROM you need to put the address into special registers anyway (which are part of the RAM for the device) so the way you want to access the EEPROM (indirectly via RAM) is the required way.
The ADC can be a bit trickier but there are lots of examples on the Internet. The ADC in the device you mention is the same or very similar to the ADCs in many other PIC18F devices so don't be put off if the example processor is slightly different.
Also, the details of how to set up the ADC can vary depending on what exactly you are trying to do. For example, are you looking for multiple channels, how often are you sampling, are you using interrupts etc..
Susan