While I mostly agree with suckyguide's post, I will try to be more constructive. :)

Summoner Spells:
I like your spells. Smite = absolutely. I prefer Exhaust as well. I love Flash, but not on Mundo. Flash is always good for escapes, but I prefer taking it on champs for defensive AND offensive reasons. It's a must on champs who can use it for offensive positioning as well.

Runes:
Your AP Quints are a huge mistake for the reason suckyguide states. With rare exception, take no AP runes, masteries, or items on Mundo - they're wasted slots, points, and gold. You're much better off with MS, APen, or even health Quints. The MPen Marks aren't quite as big a mistake, but... This is a jungling guide. The jungle creeps (other than dragon and baron) have no MR, so your MPen reds are completely wasted. MPen will help with ganking and teamfighting later, but not jungling.

Ability Sequence:
You seem to forget you're jungling. Take your R at 6, 11, 16,… yes. Max your W early,… yes. The rest is wrong. As a jungler, Q is for ganking; it is utility only. Take 1 pt in it right before you're ready to gank. While Mundo uses his W a lot in jungling, he also AA a ton, esp. at red and blue. I max my W and E together, but prioritize E. Max Q last.

Items:
Mostly good. I start the same way - CA+5HP. First b, Boots 1 and HoG. After this, decide boots upgrade - NT for more jungling or vs heavy AD team, MT for MR and tenacity, or Boots 5 to outrun Ashe's ECA. :)
I like getting WE next for the amazing AS, esp maxing E earlier than you suggest. SV next, but swap it late game for Warmogs. I like AotL and Zeke's as long as others on the team aren't buying them. I will ultimately build HoG into RO or LotIS. I prefer RO.
Now about your TF. It's not a bad item, but… 1) It's damn expensive. If you can find enough gold in the jungle and ganking, fine. 2) The mana is completely wasted, and the AP mostly.
Depending on the game, I also consider Frozen Mallet, Sunfire Cape, FoN. Some games, I'll leave a slot open for wards, esp if our support isn't buying them.

There are a few other smaller issues with the guide we'll discuss after you address these. By address, I mean either fix them or argue your case convincingly. :)

Lee

What a stupid guide. AP is the least valuable stat for mundo, he has only 1 ability that uses AP at all and only a 0.2 ratio.