The reason they don't want to do it is the full-floating axle, which isn't that difficult. For instructions, either look in your factory shop manual.
The biggest issue is installing the drum and hub without damaging the oil seal, it needs to go straight on so the seal isn't nicked. I usually use a floor jack to support the drum.
I would suggest you buy the new wheel cylinders. The old ones can be honed, but usually there is enough pitting that the old ones will need to be sleeved to use again.
Also, replace the springs. They are over 50 years old and are prone to breaking. New rubber hoses and oil seals.
Another problem can be the drums. The only replacements are used, you can't buy new. Be sure to get your's turned. There are no tricks to turning these old drums, but the machinist does need to know they aren't made new.
Also, take a picture of the brake after you remove the drum, it will help with assembly. Another tip is to only disassemble one side at a time, gives you a reference to check when you put things back together.
