Next project, redoing Ac. gonna clear all the old duct work heater core and such.. Any words of advice, recomendations on good service manuals

Get the service manual that the vendors sell. There is no order but search through and find the needed pages. I totally redid the ac on mine 2 summers ago. It was a basket case. The PO's rigged all kinds of stuff. But I found everything in the drawings. Also both of mine that have been converted to 134A have blown the hoses so you might have to replace. I was told combo of old and not used in a while and 134A runs at higher pressure