Its really pretty simple. Timing it and getting the wrist pin clips in are the hardest parts for me. It always takes an extra set of hands on the wrist pin clips for me. I'd highly recommend getting the valves ground. My 200X has next to no compression at all, was blowing oil out the exhaust and so on and when I tore it down the sleeve and rings had almost no wear. I refuse to overhaul an ATC engine like that without boring it so thats where the .040 bore comes in. No need to go that far other then I wanted to. But boring it will give you a brand new surface to work with rather then honing that just deglazes the cylinder. Also I'd recommend a simple port cleanup job. Honda left a nasty little ledge where the intake valve seat meets the head and it about has to pool gas up and restrict the flow. Just a simple blending of things and smoothing it out is sufficiant for a budget rebuild.
1984 200X bored .040 over, mild port work, K&N filter
Planning on custom exhaust, XR200 carb and cam