Way back in 1998, before digital cameras, before lightweight stuff was invented, before packrafts ...... we were one of the few pioneers to through hike from Cameroun, AZ and out to Desert View in GCNP. Very few places to get out.
No quicksand encountered. Below Blue Springs rafts are nice, I guess you could swim. Like the 2nd week of June. Timing is critical for water, before the potholes dry up. Permanent water is really bad..... typical of desert canyons. Boiling and letting it sit overnite cures most.