Oceanic Museum is just the S.S. Anne music (which is one my favorites) but with this really nice sort of solo thingy. It's really moving, at least for me.
I listened to Abandoned Ship and yes it's very sad but I think it's too sad. I'm looking for a sort of happy-sad, whatever that means. Like, moving but not depressing, you feel me? Anyways, a lot of the music in R/S/E I recognize not from the actual R/S/E games but from Rescue Rangers. I thought that destinedjagold did a very good job choosing music to fit certain moods and some tracks, like Abandoned Ship, I remember from his hack as opposed to the official games.
I don't think I'll have too many problems with the looping, though I haven't tried so I could be completely wrong. The thing is that the track is really long so I'd have to pick one section from it and loop that.
Alright I'll check out Mother 3. I'll probably look into some other Non-Pokémon games like Legend of Zelda and maybe Golden Sun. It has to be music that I know, though, or else it won't get the nostalgia factor, which, for me, is very important. I think I'll also look into the Mystery Dungeon games, too. Man, there's a lot of music out there.