C15 Severe Coolant Loss

I recently bought a 2004 Peterbilt 387 Cat C15 After with 1.4 million miles. The engine has not been rebuilt and no major repairs. The truck sat a lot for two years, only running it to keep things moving.
When I bought it, it had a dead miss on #1 and#2 cylinders. The old injectors had a rusty film on them and the shop said that the springs were collapsed, causing the miss. Two reman injectors and all was well.
I bobtailed it a while back and has a loss of power, lots of white smoke out the stack and eventually it stopped running. After it sat a few minutes, it started up and I got home OK. I felt the top of the radiator and large tube going to the block. They were cold, not cool. Cold.
The next day I checked the coolant level in the reservoir and it was empty. No leaks out of the engine or radiator/heater core. The oil was changed recently and is still clean. It would appear that all the coolant went out the exhaust.
I know that this is going to be a pricey fix, but until I pop it open, I do not know what to expect. Cracked head or head gasket are the two things that came to mind. What my questions are, other than a shot gasket, what should I be looking for? Are there tests I can do to find the culprit?
This truck is not a working truck. It is my personal truck that I bought for myself as a retirement gift. I'll need a big truck to haul all the huge fish I will be catching!!
I do appreciate any and all help you guys/ gals have to offer.
BTW. I have the intentions of doing the work myself.

 

That is about what I figured the diagnosis was going to be. I'll have to wait until spring when I can make a tarp shelter. Wisconsin winter is a poor time to be working outside!
Thank you everyone for your help. Any suggestions for a good manual?

 

Thank you, pushbroom. I'll need the manual so I have all the specs.

 

I believe that is what has got me to where I am right now. I will know more when I pop the top off and see what gremlins are there. Hopefully, the head and the block will be flat.