My mapping program says that the fastest route from DC to SF via OKC is the I-70/I-68/I-79/I-70/I-44 option. It's over 1300 miles from DC to OKC, but with good weather, good roads, and multiple drivers could possibly be done in 2 long days. It would really be better to take 2.5 days, this may give you some time to spend with your family.

OKC to SF is over 1600 miles, and this will take you 3 full days.

I-44 through OK is toll - you will have two $4.00 tolls, one between the MO line and Tulsa, the other between Tulsa and OKC.