Larry mentioned the basic areas of the 123 system to review. You have a 20yo Texas car and the system may not have had the O-rings replaced when the conversion was done.

Other places to check: The receiver dryer and the pressure switch. The 2 O-rings that connect up the condensor. The back of the compressor (2) AND just above that is another O-ring that can leak. The hi side hose connection behind the alternator (1).

You also need to check the lo and hi side schrader valves (1 each). Those can leak.

Lastly, the hoses need to be checked primarily around the metal fittings. At 20yo the rubber can develop leaks near these areas. Also check the hoses carefully under the battery tray. Sometimes a leaking battery can eat away at those hoses.

Lastly, you have sprung a leak of R134 (and the OIL) you just can't add more R134 without adding some of that oil that leaked out. Here is where my experience ends and maybe someone can pipe up and suggest how much oil to add in a sitution like this (once the leak is found).

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)