First: If you have or camp where there is "hard water" invest in a water softener of some type. That's IMHO the first step. It cuts way down on the mineral buildup and PITA to get it off. Helps on the sinks and toilet as well.
Next we use the shower spray you put on the walls after your done that you can rinse off in the next shower. Comes in a pump sprayer bottle, don't recall the name but it is Same as we use in the house.
And then to clean the shower when we return we use the "foaming bubbles" stuff in the areasol can.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!