It has been sitting over 4 years. The conversion work that was done seems of good quality, but how complete was it? Will take time to determine that.
As soon as you know the date & time you'll be there, let others know so those whose schedules will allow can make plans to meet up with you & help evaluate her.
I didn't have much trouble getting help to move mine. There are lots of us just looking for a good vacation.
You could pose it as a rally with the featured event being a hands-on workshop to get her road worthy.
If you apply your car experience, there isn't much difference in the fundamentals. Air is used for springs & brake fluid, the rest is same ole same ole - Just BIGGER!
If she will air up, - if the air compressor can keep up, - if she retains fluids in an acceptable manner, - if the tires are up to the job,
- Try moving her in the yard - if that goes well, put her on the road & ease it up to speed - if that goes well, drive her home!
Just don't flog it too hard untill you have established some history with her. . .
Take a cell phone so IF you need assistance, you won't have to walk as far.
I've priced both hook/wheel lift & Landoll. The hook has always been higher. Also, you have to have a functioning air system in your bus & let's not forget the tires.
When you lift the front of a 4501, you put a LOT of pressure on the rear axle & can over load those tires. If you let the air off it, the tail drags.
You will also find that most hook drivers will refuse to connect to a bus that old that has been in storage so long. (They may say 'no problem' on the phone, but when they see it, they may refuse & still want to charge you for the service call.
A fellow out west bought one & started out with it without realizing it didn't have water in the radiator. Lost the motor, so he called a tow. On the hook it went & down the road it went - Until a the drive shaft that was disconnected fell into the spinning axle pinion which damaged that & took out an air line which let the rear drop on the pavement. Road fix & back on the road until a tire failed which let the rear drop on the pavement, again. Finally decided to call in the Landoll.
So, focus on a landoll if you need a tow, much less risk & stress & usually cheaper in the long run.