In salem Dave's Power could probably handle it, and there are at least one machine shop nearby that could likely service the heads.
DP is always backed up though so expect it to take weeks+++.
There is or was, not sure now, an international shop on I-5 near hwy34, never dealt with them but another International shop still had some guys familiar with IDIs, never had them do anything though other than get coolant, return line Orings, and maybe injector copper washers from them. International designed them so those shops may still be willing and able to help.
There are quite a few members around the I-5 you might be able to hire out including Russ if he is able to. He's by Newberg I think. I haven't worked with him in many years but he was a great source for turbo and injector/return stuff back then, but either was too busy or had life stuff where he couldn't help with my specific issues. I don't really recall now, it's been so long.
These jobs always seem daunting, you'd want a driveway and small garage space to DIY it, you could rent a month at a storage unit for less than an hour or two of a mechanics time... I swapped my engine out in a weekend after scoring a UHaul reman after I went through it and prepped and converted and overhauled it from sitting in storage, and being a van style engine I had to swap exhaust manifolds and oil cooler ears. I did that in a driveway fighting to get the cherry picker in place without it tipping or rolling away, with barely enough room for my supplies in the garage in a weekend in the rare Oregon Valley snowstorms. It was raining on a Friday and sticking Saturday as I had the front end tore apart. Had to get it done. If I can do that with never having pulled an engine, you could pull the heads and drop them off to a machinist for a rebuild, and pull the trans out and swap or drop it off, there's a few dedicated transmission shops around and the 4 speed is super simple. I never tried it but I think you could pull the driveline off the transmission or 4x4, jack up a transmission jack under it, and unbolt the 4 or 6 bolts from the engine. Not sure, ask these guys they'll know. If you let fear of the unknown stop you you'll never do it. If you can afford a mechanic have at it, I'm guessing both jobs would be about half the value of your truck in good shape.
Good luck.