Refrigeration on a vmc110

Hello,
I am stripping down a VMC 110 machine that I have had for 3 years (well its about time), getting ready to restore the beast. I had never plugged it in because the cord was frayed and the junction box was busted. After reading some of your other posts, I unplugged the compressor cord and plugged it in to an extension. Low and behold, it started working and the fan next to it also worked. Since it is 10 degrees outside, I cant tell if it is getting cold. (dont worry, its in the garage)
My question is; it is probably low on freon and since you can't use r12 anymore, what is the perfect replacement gas. What is HotShot gas? A refrigeration guy once told me about MP-39, ever heard of it? I think if you use 134a you have to add castor oil. Any benifits?
Also since it is at the point that it can be worked on, are there parts that should be replaced on the outside of the compressor.
What is a dryer and should it be replaced. Also would it not be of benefit to solder high and low pressure connects on for easier filling? Anything else I have missed?
This is one great sight, and I've been to them all. Thanks to all the helpful people.
Compressor is a 1/4 hp (pancake) style. I will have a pro put the gas in, but was just wondering if there were other things that I could do in the mean time.

Pope

pope, this is a perfect question for eric at global compressors, but i will give you my advice from experience. with things slowing down in the trades i would call up a refrigeration tech out of your local phone book and for as little as 50.00 depending on what part of the country you live in, he will trouble shoot your machine in 15 minutes and let you know the problem and the costs to repair it. i had bought a pepsi 110 in the middle of winter and when i plugged it in, the evaporator line began to freeze up. so i assumed it was working. then summer came along and i plugged it in,  and the line still frosted up but it would not get cold enough to cool. called a tech and he diagnosed a bad valve in the compressor. so then he put in a new deck for 500. and now this thing cools like a champ. i did all of that after trying to repair it myself which took hours. i had the guages, evacuated the system. i bought the aftermarket freon, and still hit a deadend. if you don't know how to read your guages you will never figure out the problem. so my advice is save your time, spend the money and have a expert fix it. that is why he gets paid the big bucks