How do you replace all the tires on a 5th wheel?

I put the spare on and leave one on the jack. Take the two down and replace. Repeat for other pair, done. Yes I jack on the axle U-bolt to lift it one inch.

I also supply my own stems and insist on lug centric balance.

X2---- I always have metal stems put in the rims. They have less air loss and you don't have to worry about rubber rot occuring on the air stems.