Before you go make a crazy decision-like stop being a matis, my main character is a Matis-Kami follower. The only hard part about being a matis-kami is doing a few extra missions to gain kami fame. But I promise you, it's worth it

You wont find any Matis aligned Kami guilds (unless I'm missing something), but I know of quite a few Kami players that "hang out" in Yrkanis. I used to keep my packers there, but since I'm to lazy to turn off my faction tag most times-eh, well, dying while crafting sucks
Would I be able to find a guild that could help me out in those lower levels, or will I be half a world away from them?
Most guilds have higher level players-which makes trekking a lot easier. For example, my guild, Team Spirit (a tryker-kami guild) is known to trek a lot. Many players enjoy trekking people, and many players enjoy helping new players. Unless you run into one of the super-RP Karavan, being Kami will not effect you or your game play.
How many Matis players have gone Kami? And is it a tough row to hoe?
There are not a ton of Matis-Kami, but it's always fun to be in the minority. And I promise you, it isn't "a tough row to hoe."
Good Luck. If you need help with anything, send me a /tell ingame or a private message here on the forums and I will be happy to answer your questions.