Freightliner Columbia 12.7 inframe

[Eby6114]

I have a second hand Freightliner 850,000 miles that when changing the oil found about a quart of antifreeze in the oil. I was trying to find someone local to do an inframe most are backed up or just plain expensive. One place quoted 18,000 best case scenario, 26,000 worst case if it can be saved. In the meantime I guess I'll find some wood to jack up the truck so I can drop the pan and do a pressure test to see where it might be leaking. I'd probably tackle it on my own with a bit more experience and a garage, somewhere to work.. I watched quite a few videos on it. Ive offered to tear everything apart minus the head, Jakes, etc to help out a shop but 3 weeks backed up is 3 weeks backed up. That's if they'll even call you back.
Tools I'm lacking besides a clean working environment, counter bore, feeler gauges, dial indicator, ring compression tool, giant torque wrench, cam holding tool etc. Ive done a lot around an engine not much inside. I'm in the Wildwood Florida area. Any advice that you want to give is appreciated. I'm opting towards waiting on the closest place in town.
There was one gentleman that shared his rebuild process on the 12.7 but I don't think he did a counter bore or used a dial indicator on the liner installation which raised red flags to me.
I've never seen any white smoke or seen any blow-by. Did a hydrocarbon test in the overflow tank running the truck for 30 minutes and the chemical never changed color. (Blue good, yellow bad)
Thanks