Are you saying that the playlist will change depending on your mood or the occasion, or are you intending to make one main playlist that you can continue to add music to?
If you just want one playlist, then I suggest picking all of your music that you want, transferring it from your computer to your device (making sure it's in the correct Music folder), and then in the Play Music app, selecting "On device only" from the top dropdown menu. This will prevent any songs from the cloud from being listed.
Sorry if I'm misunderstanding you--I'm not sure if my suggestion completely meets your needs.
By the way, keep in mind that stock Android music players are often lousy at categorizing music correctly by artist. The main problem is that if you have an album with songs by various artists, Android will list the album artist as the one from the last track of the album, rather than "Various Artists." They've never fixed that bug. Some but not all 3rd party players get around this bug, like PowerAmp and MortPlayer.