I'm not able to give you a direct answer at this point so you can read the following rambling response, or not, with that in mind.What would be fair for what I listed at a shop?
Were they going to do all of the work you listed including the dent pulling, providing/installing the new tires, etc.? What does "Diff service" include in this case (new gears/parts or just fluids)? $6k for the cooling system refresh is well beyond what I can imagine for that work, and I have a pretty capable imagination
Shop costs have gotten a bit wacky and inconsistent these days and high quotes can be the result of a variety of causes, not all nefarious. The general "make it road worthy" request that it seems like you made may be why the quote is so high because they are essentially agreeing to take on the risk of this older, unknown rig. Conversely, it's also possible that they see dollar signs and are planning to cash in without doing much actual work to the rig. I can't say either way from where I'm sitting.
I'm assuming you may not plan to do your own work on the rig, which I think is a good way to go if it fits your situation and you can afford it. I prefer to do all possible work on my cars but know that this approach isn't for everyone. In any case, the more you know and the more specific you are in your requests from a shop/technician the better the results will be. Hopefully you can find a mechanic that meets you where you are and works on your rig(s) the way you want. Ideally they are familiar with LandCruisers and know the tricks of the trade with these.
Anyway, back to your situation/topic. Even if the quote were lower I still wouldn't send the 80 in for a bunch of work just to make the initial trip home unless it was with a known very-high-reputation LandCruiser specialist shop that you wanted to take advantage of being near before retrieving the 80. If the 80 has specific issues keeping it off the road I'd trailer it and have the work done closer to home. If the 80 is driveable as it sits I'd do what I shared above and make the trip, possibly upping my AAA coverage to include a 165 mile tow if it seems sensible to do so.
Overbuilt reliability is the single best attribute of these 80s in my opinion. Generally speaking you have to do the maintenance to get that reliability but that doesn't mean you can't lean on the 80 from time to time to get you where you, or in this case it, needs to be so that you can catch up on the maintenance on your own terms.