Mahler is my favorite musical artist in any genre. Tunes! Emotions!
If you can tolerate classical vocals, try "Des Knaben Wunderhorn" recorded by soprano Maureen Forrester, bass Heinz Rehfuss and the Vienna Symphony conducted by Felix Prohaska. It'll instantly take you back in time to fantasy Medieval days. Solid sound quality, too.
Mahler's First Symphony inhabits the same magical place. Try Bruno Walter's old recording, in pretty good sound, as well.
The Fourth Symphony is gentle, easy and, again, filled with fine tunes. The final movement is the proverbial child's vision of heaven.
Mahler's Seventh Symphony can get more than a little long in the tooth but the final movement is glorious & friendly.
In any event, Mahler creates complete musical worlds, worlds you find yourself wandering around in.