Is this still a good guide?
 

not really since a good portion of the locations are on luclin :P

18-25:Bandits in Paludal are amazing grouping xp and can solo in the mid 20s.

25-30:Marus seru mobs are pretty tough for level, but a change of scenery from LOIO

Paludal and Marus Seru are from Luclin so are Rockhoppers. Some of the stuff is from velious as well. Prolly need pretty good gear for some of the later stuff. Overall it does not look bad.

Where would be a good place for my level 33 monk to go?

I leveled to 40 pretty quickly in MM. You might not always get a group but it usually wasn't an issue.

Kill guards in Highkeep.