Re: kayak setup
Ted speaks the truth. If you are only fly fishing, you don't need much-- nothing more than what you'd normally take with you. Less is better.
You probably aren't thinking in these terms as 'setting up', but a good seat is a must. A good seat will mean the difference between an hour on the water and several hours or even several days in a row (such as a fishing trip).
I don't necessarily agree with the paddle suggestion. I will say that lighter is better, but (for me) the paddle is only in hand when I am getting to a spot. the rest of the time, the rod is in my hand. (If I had to estimate, maybe paddling 30-40% of the time I'm on the water.) The rest is drifting, or floating. I think that money is better spent on a good seat. (if money is no concern, then go all out on everything)
If you fish both fly and spin/ cast, etc. I fish with guys who use a milk crate type box in the back. They will zip tie lengths of pvc tubing to the box for multiple rod storage. The down side is they stand straight up-- which limits some of the tight spots that you can get into-- need to stay aware of whats above you. The box is storage for tackle boxes, and such.
(Flame suit on-- I know I will take heat for this) I don't always wear a life jacket, but always have one in the bow hatch of the boat. you will need PFD on any body of water you go on. figure this into the cost. Small/Still water-- don't wear it, moving water or bigger water with bigger boats, always wear it.
there's more that I could type, but will let others chime in. always good for a few different opinions.
//EDIT// I re-read your post--- when you say you are getting caught up in brush, do you mean during your casting? A kayak is an awesome way to explore water and fish water, but it shouldn't be a substitute for good casting fundamentals.
There are ways to cast around trees and brush and not get hung up (it's bound to happen, but with experience you can keep the tangles to a minimum.). Much of staying out of them is just knowing where your back cast is and what it is doing. I know this sounds vague, but it will become second nature as you cast more. without thinking about it, I will use a 'steeple cast' when I need to (for bushy stuff on the ground), a side arm cast will keep you out of most of the higher hanging stuff, and a roll cast will keep you out of about all of the stuff....
He who loses key to girlfriend's apartment gets no new key. ~Confucius