This may be a dumb question...

I have most of my music on a Synology NAS drive that I listen to via a PS Audio DAC II network bridge when I'm home. These files are all stored in FLACC. I also have an iPAD II that I want to use to listen to my music when I'm away from home. How do I copy that music library to my iPAD in Apple's lossless format so that I can have it on the go? I can't find any info in the user's guide. Thanks in advance.
You need program that can translate formats, like (free) MAX. MAX is ripping program for OSX but it translates any format to any format as well.
Since you are using FLAC files I assume you are on a PC and not MAC. What software doe you now use to import your CDs as FLAC files? That software (dbPoweramp, EAC etc) should have the ability to transcode the files to ALAC, AIFF or WAV for use on the iPad. However in order to synch your music to the iPad I think you will have to manage those files with iTunes.
I used dbpoweramp to burn my CDs to a Synology NAS drive all in flac format. Now I want to take some music with me and listen on my iPad. Can I connect the iPad to the NAS via USB and copy the files or should I use dbpoweramp on my windows pc to copy the files and transcode them to apple format and then sync my iPad to my pc? What apple format should I t ranscode to for use on the iPad? Thanks.
I'm not an expert but I think you need to use iTunes to place and manage files onto an iPad, and I don't think Apple products can play FLAC, so you need to convert to a format Apple can play.
Disclaimer: I'm a PC.
There is a product for iPod 4G and the iPad called "FLAC Player" that will play FLAC files on an iPod or iPad.

Using the iTunes interface, you can move and play FLAC files to your iDevice.

I bought it and love it - no need to convert.
There are a few options if you don't want to transcode.
You can put the Flac files on a Seagate GoFlex HD (500GB), it will setup it's own wi=fi network so you can stream to the idevice, play the files using 8player.
You could also use Fluke,it will put the flacs in a container that can be read by itunes.