A/C question
I still remember driving my 82 S-10 for 10 years in Atlanta. I bought it new w/o AC, manual steering & tranny in 1982, yep the cheap one in the ad. Still remember suffering at stoplights in the sun.
AC isn't as expensive as you think. You already have the under-dash stuff. I wouldn't put back the factory RV2 because it is a heavy beast, though they rarely fail (sure yours is bad?). You can buy a new small & efficient Sanden for $50 (I have, winter on ebay). It looks easy to mount a "York to Sanden" adjustable bracket ($50 ebay) on the block pad where a power steering pump goes, or if you have p.s. get the Sanden brackets off a Volare or Aspen (I did), plus the Saginaw p.s. pump. For much more (~$200), you can buy Sanden brackets for a slant. Find an AC shop, or a guy w/ an AC crimper (like me) who can make hoses. Should be easy to attach to your existing fittings since the rubber hose is standard sizes.
Re refrigerants, you take a risk installing R-134A today since already outlawed in many countries, though plan is to still be able to buy recovered stuff until 2030, but might get priced like R-12. I use HC refrigerant (Duracool, also Envirosafe) in all my cars now, even my 2002. But, it scares many people, so read the imagined horrors. If scared, use R-12 for now since HC is compatible w/ the mineral oil and you can change later if you get brave (and EPA isn't watching, read their stupid rules). So far, there have been 0 reports of fire or other incidents in millions of cars using it for decades. If changing oils, look at Hella's PAO 68 (ebay), since it works w/ all refrigerants and is more efficient. If you install PAG oil (for R-134A), you will be orphaned, plus it absorbs moisture and makes corrosive acids if you ever leave it without pressure.