To be honest, removing the intake and heads should be able to be done in under an hour. The intake has 10 bolts, heads 8, exhaust 8 and these are the hardest part, spark plugs, coolant drain, etc. The lifters are readily removable as they sit in a tray and are not down in the block like an old SBC. The rocker arms are on a shaft and no lash to worry about either.
The lifter issue has effected many vehicles, not just GM trucks. Mopar has had an issue as well. The 'bad' lifters are failing due to oil restrictions which is the basis of how the AFM works, reduced oil flow collapses the lifters and that reduces the number firing cylinders. These rigs run extremely low oil pressure to begin with to improve fuel economy. It takes a milli-second to have a lifter running on the cam without oil to have enough friction to cause a problem. The camshaft is hardened and the lifter roller surface is too but there is not enough mass in a lifter to absorb heat which leads to a surface failure.
Solution: Probably none for the average person who just takes the truck into a jiffy lube and spends as little as possible on an oil change. Then the guy that goes into Walmart and buys the cheapest oil and filter to do it himself. You have to use a high quality oil that is designed for our trucks. An oil that is going to provide protection at 15 to 20psi is night and day different than an oil that will protect at 50 psi. Oil filters are also extremely different. Every filter has a built in pressure bypass valve in them, meaning if you buy a cheap filter with a cheap or defective bypass, the oil will flow straight thru without being filtered. This valve is designed so that if the filter gets clogged, the engine will still get oil. a quality oil filter like WIX, Baldwin, Amsoil, etc have bypass valves in the 20-23psi range whereas the cheaper filters are in the 15 to 18psi range, so as the filter cleans the oil and removes contaminates the pressure builds up and the oil filter bypass stops filtering the oil. This is as important as the filter media which I can talk about all day. Go over to Bob the oil guys website and you can see countless pics of filters that have been cut open with crap filter media.
Sorry, I've rambled. I always run Baldwin or WIX oil filters with a Dexos or European spec rating in just a tad higher weight, 5w-40 instead of 5w-30. Its changed either at 5000 miles or when the oil life monitor gets below 20%, which ever is first. I live in Florida and the heat plays a role in this. My oil pressure is more stable, the engine is quieter and I even think my mpg improved a little. I also run about 2 oz of Marvel Mystery oil thru all my cars every other oil change. I think it eliminates any sludge inside. I also have a 3 turbo BMW's and a 2013 Z06 vette and run the same oils in all of them.
Tim