1999 Tahoe Ignition system

[Jeep_Comanche17]

So just picked up a very nice Chevy Tahoe to fix up and get running. It is a GMT-400 platform truck, manufacture date is 08/99, so one of the last OBS Tahoes. One of the issues that needs addressed is the ignition tumbler. apparently the tumblers fell thus the key not being able to go back in. so he removed the column and stopped there. now, as I understand, the key has to be in the ignition tumbler in order to remove it from the column. so im thinking it just going to be easier to install a complete junkyard column. my main concern is anti-theft crap. I know it has caused several guy on here major headaches, and I definitely don't need that. so what would be the best way to go about fixing this? also how hard is it to replace valve lifters? previous owner said they might be starting to collapse. this is a 5.7L vortec auto Z71 4x4 fully loaded truck. thanks!