basically, if it has a gas motor, which it has to because that's why it's got the pony to save fuel, hydraulic brakes and a 2 speed rear, it's worthless.
Because the 377 motor gets 2 mpg, anything without air brakes is a problem, especially when you leave it sit a lot which you are probably going to, and nobody can shift a 2 speed anymore.
so, your resale value is zero on that rig.
Most importantly, if the boom hasn't got a current inspection on it, stay away.
for 20k you can get a nice utility bucket truck with a good certification, but it's still really easy to get screwed on these used buckets no matter how hard you try.
you want to look at the hours on the boom more than the mileage on the truck.
the other thing to keep in mind is that a tree truck is used for everything. pulling the chipper, chipping, hauling wood, aerial work, you name it. utility buckets are easier on the cab and chassis.
I just bought a 2000 GMC utility for 18k.
so far, I've rebuilt 2 outriggers, replaced the main collector block and put several hoses on it to the tune of $3,000, and that's with me doing all the repairs. I shouldn't have paid over 14k.
This is what you are jumping into with these old units so be prepared to pay.