If you have access to an air compressor I would blow out the condensor, remaining lines, replace the orifice tube and remove all oil from the condensor and compressor...
After being open for a year, even though PAG oil supposedly is not hydroscopic, I would remove the oil for wanting to remove any dirt or foreign matter that would have gotten into the system.
By removing the orifice tube you can see the state of your refrigerant system... If the tube has brown or black flakes or melted plastic/teflon pieces you will need to address those problems... The only place this debris can come from is the compressor and this junk can clog the condensor and lines leading up to black death...
Change the accumulator...Its job is to remove moisture from the refrigernat and once the system is opened you do not reuse it..Same with the orifice tube...Its job is to provide a metering restriction in the system and to filter out any debris and garbage in the system... They do wear out, get old, and stop working over time.. Whenever the system is open, take the time and opportunity to shotgun the parts in the system and replace any wear or maintenance items.. Think of the orifice tube and like a tranny filter and the accumulator like a permanent oil filter... Both just require more work to replace than those filters on the engine.. But since the refrigerant system is more sealed than your engine, there are fewer opportunities for dirt to enter and less need to replace these filters.
Tools... You are renting gauges and vacuum pump..Good first step...To remove the lines on most Fords you will need a set of disconnect tools.. They are similar to the same tools used to disconnect fuel lines on Fords... I have both the plastic set and the aluminum set...I use the plastic ones until I can't get the parts apart then I use the aluminum ones.. Also you MAY need an orifice tube puller...Sometimes a pair of needle nose pliers will work and in some cases the orifice tube is part of the line that it is installed in and cannot be removed. In that case the line needs to be replaced...
Repairing the system... Since this is an R-134a system you can't guess[ or should not guess] on the charge amount...A proper charge level is based on the weight of the charge and ideally a tank with a scale should be used...Now since most of us do not have those tools we rely on the guess and pressures method..We use one large can or a couple of smaller ones and watch the pressures go up and feel the inside air cool down and stop when it feels good to us...
You can remove all the oil in the system then replace the o-tube, accumulator, the broken line, all the o-rings on the fittings, add 7 ozs. of the recommended Pag oil then attach your vacuum pump and run it for 30 mins then shut it off and check for leaks.. If the system holds vacuum, then run it another 60 mins to verify the system is good and dry...At this point you have 2 options... Use the guess and pressures method or take the vacuumed and repaired system to an ac shop to have them recharge the system with the proper level of refrigerant...
Both ways work[ I have done both] but I prefer the weight method in the system and that way I don't have to wonder if I got the correct level of refrigerant in the system...Pressure wise you are looking for 2.3x-2.7x ambient temp on the high side...Low side will vary as the compressor cycles on and off and the heat load from the inside air changes...
One last item to look at is the engine driven fan and clutch and the condensor fins...Make absolutely certain they are functioning properly and the condensor is not clogged with dirt, bugs, debris, etc...Both will need to work harder to keep the engine cool and the vehicle cool so anything you can do to facilitate that helps not put more load on both.. If the fan clutch is marginal. now is the time to replace it...Clean the condensor now if needed while the system is apart and easy to remove from the vehicle...
I think that covers most bases on your system...
