Ok that clears things up, still not sure on the reason for the motor swap outs though but I completely get the rest and welcome to the addiction, I also have it BADDDD.
Since you said it's hard to control your 450 and you have negative expo on it I'm curious why you'd want to go to a smaller more nimble craft? If you want to fly fast and dodge trees the QAV500 or the ever famous TBS Discovery Quad is the way to go hands down and you can convert you 450 to a TBS quad which I believe is how most people end up with one. Going to the 330 is probably a bad idea honestly as there are better choices like the later which you'd really enjoy a lot more I think. Generally speaking, much like with aircraft, the bigger it is the more stable it is and vice-versa is true. If you want to film you'll need stable, if you want to dodge trees you'll need small, light and fast so the two are counter to each other but there is middle ground and I'd be more than happy to help you find it. I started with the DJI F550 which I built from hobbyking and it was the knock-off kit. I picked all the parts separately which I personally prefer because it saves you money as well as it's super fun, for me at least, to build.
Better than learning to fly line-of-sight and then switching to FPV is to go straight into FPV and start in GPS mode or attitude mode which ever you prefer. Flying line-of-sight is nothing like flying FPV and if you want to learn FPV without risking your craft get a computer simulator you can hook your 8FG to and learn like that. Something like the PhoenixRc HD 1080p Version 4 simulator is invaluable and you can use it for learning to fly anything pretty much. There are other cheaper versions out there too like the AeroSim RC simulator, I put links to both on YouTube so you can see them in action. The only thing I'd say is make sure you can hook your controller up to them so you can learn on the same controller. I used a flight simulator and I still do to practice and it's almost 5 years old now so they really are worth it and help tremendously on honing your skills.
http://www.youtube.com/watch?v=AAuYGbjDpcQ
http://www.youtube.com/watch?v=9gCi8Qz9VD8
As far as radio and video goes if you have a lot of obstacles you're going to have to go with low frequency everything. UHF radio and 900Mhz or 1.3Ghz video and when you go to get those we can address the issues with each and using both together. I'm sure you know a little bit about radios and frequencies already but the basic idea is the lower the frequency the less power you need to go the same distance as a higher frequency and the better the penetration. For example, 5.8Ghz takes more power to go 1 mile then 900Mhz does and 5.8Ghz will not penetrate anything very well at all so flying around trees...no way but we'll get into that later because there's a lot more to it.
As far as flying in the trees goes, I'd say you're going to have to step up and be ready to fly above them and be ok with that knowing and accepting the risks if you're going to fly on your own land. But again, the best way to learn FPV is to do it or do it in a flight simulator. Flying in a big open park with nobody around is the way to go once you are comfortable.
Side note, I grew up in Oregon in the Eugene and Roseburg areas and I know the coast area well. I went out there not to long ago to visit my parents but couldn't take my multicopter because it wasn't finished yet but that area is going to be spectacular to film. The biggest issue you're going to run into in filming and flying out there is the insane wind which MR's do not like much at all, they get blown around easy.