question(s) for the Mechanics

My guess under 2k. Not sure about 5 wheel what’s actually wrong with it?

 

This is SHOPS priority list:
seals and engine oil leaks first.
A muffler would be nice; along with a fifth wheel.

You could pull the passenger door inner panel and see if linkage is just stretched out.
Horn and lights are possibly wiring or bulbs.
You could buy fire extinguisher and extra triangles from a truck wrecking yard.
Not a whole lot wrong here, mostly labor and parts.

This is YOUR priority list:
(Can't you do any of this yourself????)
Go get your hands dirty, you'll be glad you did!
Start with the marker lights on roof; pull the bulb and see if filament is broken.
(Possibly replace all with LED Bulbs, while you are doing it.)
get a test probe and see if there's juice there, then move to next one. DONE.
Horn, test the unit off a battery first, if it's good - it's the wiring - replace it. DONE
Next wire ties on all the hanging fuel and air lines. DONE.
Pull rocker shaft cover, replace gasket. DONE.
Easy-Peasy, and you just PAID YOURSELF about $250.00!
None of this is high dollar, unless you need to totally replace fifth wheel.
Again, a truck salvage yard would have one in great shape for less than half new price.

 

Truck is old enough that the electrical will be fairly simple to T/S. Say 3-4 hours to diagnose electrical, repairs above and beyond.

Wheel seal say 2 hours. Pinion seal could go either way. U-joint might just pop right out or she could be fused in there with rust. Worst case Ontario say 3 hours if the u-joint is being ignorant.

Loose lines could just be a matter of zip ties or P-clamps. Shouldn't take much time.

What engine? We'd need to know in order to ballpark a time.

Muffler could take a couple hours. Exhaust can be pretty ignorant when its rusty and depending where the muffler goes some mounts/hangers may need to be sourced or fabbed up.

 

You never know what you can do unless you try. For what its worth trucks (especially one of your vintage) are easier to wrench on than cars.

Sorry I can't help with the engine leak. I haven't come across a Cummins of that vintage. More of a CAT guy.

 

Think tool cost verse giving your money away to someone else. then you have tools for next time, even if it is some cheap frighting harbor tools.
You can learn a lot on You tube , an call around to shops some people will tell you how to do things if you are unsure

 

Those Cummins had O-rings at each end of the the rocker shafts. There are three of them. If one is bad they all need replacing. Replace the o-rings on the fuel jumpers between the heads and under the plates at the ends while you are there. Adjust the valves and injectors as well. A 4 or 5 hour deal I thank for an experienced hand.