Where do I start A/C repair

[deadshort52]

I just bought a 71 c-20 camper special with a 402 motor. I am starting to work my way through it to make it road worthy and I want to repair the air conditioning. When I bought it the belt was taken off the compressor. I am looking for some insight on where to start. There is a little pressure still in the system so I don't expect any big leaks but I am still wondering where to go from here.

Thanks in advance for your responses.