To the OP, just go in with your eyes open. You can easily spend $2500 getting up to date on the obvious maintenance. This is changing all fluids, checking all rubber hoses/lines cooling and brakes, etc. What condition is the suspension and all bushings? Does it have obvious oil leaks? Is the front axle leaking grease? How does the engine sound? This is just the highlights list. You mention having it look nice for work, this can be a real can of worms as you mention body panel rust.
Does it have factory front and rear lockers? Factory lockers in working condition can get $1700 by themselves.
I used to need my Land Cruiser as my main vehicle. At the time I commuted by bike so it wasn't a DD per se, but I did need it to pick up kids and the like. Doing major maintenance over the weekend was always stressful. I had to anticipate all parts needed and couldn't go through the inspect-replace as needed. There was the stress of what to do if things went sideways. When I picked up a second car all this stress went away. I could take my time and just plink away at things. It is now part of my relaxation time. I just did my second front axle service 15 years after the first one. It actually took a month of plinking away at it. I discovered my spindles were worn, so a delay to get those. Then discovered the birfields needed to be replaced, so another delay. Oops, late-model birfields need late-model drive flanges. I then took the time to paint the axle and knuckles. During assembly I mangled an axle seal. No problem, it could be down for a long time.
I could not have afforded/justified owning my Land Cruiser if I had to pay someone to work on it. For instance the AC compressor went out, actually grenaded. I was quoted around $2000 (I can't remember the exact number, but it was big) in parts and labor to replace the compressor, condenser, drier, thermal expansion valve. This included flushing all the lines and charging the system. I did it over a holiday weekend for about $500 in Denso parts. Lather-Rinse-Repeat for axle service, oil leaks, u-joints, EGR system, etc.
I love my Land Cruiser. I'm glad I own it. If I could pick up a project cruiser for $1700, I would probably do it if it was in generally in good condition. I would definitely do it has factory lockers as I could dump it with out loosing money. I would not do it if the cruiser was going to be my main source of transportation or if I had to pay some one to do the mechanical work.