You definitely have your hands full. Sorry about your dad.
I remember owning Ruger MK3, disassembly/assembly is such PITA, though it is a very nice gun to shoot. I replaced a sear, extractor (after it broke), and slide stop after it also broke, all parts by Volquartsen. My MK3 had some rough edges literally and figuratively, got various grit sandpaper and spent about an hour went over the whole gun, frame, upper, and bolt. Put it on a steady diet of match ammo and never had any issues.
I remember owning Ruger MK3, disassembly/assembly is such PITA, though it is a very nice gun to shoot. I replaced a sear, extractor (after it broke), and slide stop after it also broke, all parts by Volquartsen. My MK3 had some rough edges literally and figuratively, got various grit sandpaper and spent about an hour went over the whole gun, frame, upper, and bolt. Put it on a steady diet of match ammo and never had any issues.