Unfortunately dust can be a serious problem. My 5D always has dust on its sensor. Blowing the sensor off gets it to manageable level. The other day I grabbed the camera and started to use it, only to find 20+ dust spots on each image! The biggest impact is in landscape shots where you stop down and have something like blue sky that shows them well. Wide open aperture blurs them out and they are not visible. If you only pull out a handful of images per shoot, then it is pretty easy to remove them in photoshop. The healing brush these days is very good at removing them. If not, the clone brush will do it if you are careful and find an area that has similar pixels. The ultrasonic shaker in my pro cameras is very good at keeping dust away.
On tripod,
the standard is Gitzo carbon fiber. They are extremely light and importantly, extremely reliable. I first bought a different brand of carbon fiber (bogen?) only to have one of the leg locks fail. This was a dedicated wildlife photoshoot in a remote area and I was out of business trying to hold a massive telephoto lens without it working. The Gitzo is insanely expensive, in the area of $500 you noticed. They used to have a serious flaw where you could not lock each segment of the leg in random order. The "6X" series fixed that a few years ago. I have not kept up with them to know if they have something new. But the 6X series is perfect. Note that they have a wide range of tripods and you will need to seriously examine which one fits your needs. I could not decide and I wound up 6 of them or so!

For example, I have a massive one for my wildlife work with massive lens. While as carbon fiber goes, it is very light it is still bulkier and heavier than my ultralight versions.
Here is a cool thing. I find that even the smallest, tiniest Gitzo carbon fiber that has legs smaller than your finger, I can put massive cameras and lenses on them, way being their spec! So don't be afraid to undersize if weight and packing size is important (it is for me as I don't like to check my critical camera in when I fly). Not saying you should undersize but don't feel guilty if you have to. If you have IS it will compensate for increased vibration.
BTW, if you did not get a cable release, you need one for landscape work. For wildlife I do not use one as you need speed to catch the action and finger works much better than that. But otherwise, the cable release helps a lot with keeping even lightweight tripods stable.