Alright, here's the deal. I'm really interested in getting into the Monster Hunter series, but from all I've heard, this is really a game to be played with multiple people. It's designed that way. Unfortunately, since I'm a lone gamer, living in an area where I'd be lucky to see a PSP at all, let alone a gamer also playing Monster Hunter, I'd have no chance to experience it that way.
 
So is the game any fun to play solo? Is it really worth it, in that case? I'm starting to think moving to Japan would be a better option...

It's ok single player, it's fantastic multiplayer.

They were more accommodating in this entry with the inclusion of Felynes (i.e. a combat assistant, and a cute one at that). It's not the best replacement for a human player, but it does a great job with baiting monsters. I stopped playing this game after the first set of quests because it got too hard to solo. However, that was primarily due to my own stubbornness in not wanting to switch to an equipment set I wasn't used to.
 
There's a lot of great value in this title, even as a single player experience. I believe a demo is out there somewhere so you may want to download that first.

*bump*
 
I've soloed this game all the way to the last boss, so I'd say it's worth it. The game has a lot of depth and challenge as a solo game; the strategies and tactics are a bit different from when you're playing co-op. It becomes almost like a 3D fighting game (for people who don't have the reflexes to handle 1-frame button inputs) with lots of RPG elements. 
 
However, the combat system might not be to everyone's taste. I think there's a demo on the PSN store - would recommend you try that and see if you like the way the game moves. If you dig the way the game does combat, it's definitely highly recommended even for solo play.

I was just checking up on some multiplayer options and found a couple that allow for online play: 
1) If you have a PS3 you can make a japanese PSN account and download adhoc Party
2) If you don't have a PS3 you can use Xlink-KAI, it's not as solid but it still gets the job done.