Cables provide minimal (if any) improvement in SQ. Really not worth worrying about until you get into more expensive IEMs/headphones.
Are you in the US? FiiO X3 is $150 from B&H photo through today
. I think that's your best deal for the reasons alpha421 mentioned. Plus, I think it's good when traveling to have a separate music player so you don't accidentally use up all your battery in your phone.
However, for backpacking, I have a nice DAP, but I would take my Sansa Zip or Sansa Clip+. Weight will really matter to you while you are on your trip. Extremely small and light weight with excellent SQ. Takes microSD cards for extra storage. So for about $50 to $55 bucks, you could have 32GB of storage and a good sounding DAP.
Otherwise, B&H has the E12 on sale, too: http://www.bhphotovideo.com/c/product/968290-REG/fiio_e12_mont_blanc_pro.html
. However, for backpacking, I might go with the C&C BH for it's much smaller size and battery life: http://www.head-fi.org/t/644363/c-c-bh-portable-headphone-amp-80-hours-from-a-single-charge-buyer-review
. Weight consideration again. If you are interested, I was planning on listing mine for $65 shipped (I just don't use it enough and have an E12, too). Send me a PM if interested.
Tenore Carbos can be purchased from Amazon prime: http://www.amazon.com/AUDIO-ear-stereo-headphone-Tenore-ZH-DX200-CT/dp/B0093VVP0Q/
I would also suggest looking into the Havi-B3 Pro and Ostry KC06. These are generally considered comparable in class (and price) to the Tenores with some people liking their sound signature better. Penon Audio is pretty quick on shipping:
Lots of discussion about those three IEMs in the Chinese/Asian brand thread: http://www.head-fi.org/t/684159/chinese-asian-brand-info-thread-headphones-iems-amps-dacs
Research and ask questions there.