I think you're on the right track. See about getting some training too. I took the basic fire extinguisher training at work a few years ago and then used one for a fire at our house last Christmas and put it out.
I'm a big fan of our firefighters (dad was a fireman), but it takes time for them to get to you and it can spread quickly.
The extinguisher worked and I put out the fire and didn't have to call 911.
Your exits are more important than the extinguishers, but put a few extinguishers in strategic spots. I keep one in our bedroom in case I need it to get out (faster & easier than jumping out the window). I also have one in the kitchen, one by the door, and one in a cargo hold next to the emergency triangle.
People are more important than "stuff", but every bit of protection helps.
In our off-road riding group, the assumption that your extinguisher probably won't help with YOUR fire because the available locations are so limited and they need to be near the engine where the fire will probably start. So YOUR extinguisher is really for your buddy's fire. And hopefully he has one for your fire. Keep that in mind if you see a fire in your neighbor's camp. It's very possible the neighbor won't be able to get to theirs.
The other thing to keep in mind is what a horrible mess they make. If you jump the gun, the damage from the mess can be worse than the fire. If you can aim for the base of the fire and give it a few quick PUFF-PUFF-PUFFs to see if that puts it out, then you can keep the damage to a minimum. If that doesn't work, then you can hit it again and hit it full blast.
Just take care of yourselves and your family (and pets) before you try to save your property.
Take a look from time to time and make sure nobody in your family got "helpful" and moved the extinguishers from their locations. And make sure to remind yourself and your family where they're located and how to operate them.