From my experience, interiors need to be CLEAN. Exterior at least washed, dressed, waxed, no waterspots, shinyish "improved" paint
I do the same level of work for 3 used car lots.
Here's what I do
Hyper quick vacuum, like very very quick
Air purge interior really quick
Revacuum
Prespray carpet and upholstery chems and agitate
Pre spray engine bay with apc, agitate, rinse
Prespray tires, wheels, wheel wells, door jambs with apc, quickly agitate, rinse
Spray Meg's wheel brightener on wheels, agitate quickly, rinse
Rinse whole car, wash, rinse, blade dry
Lay down carpet/upholstery shampoo from bucket, then extract
Blot carpet and lift extra dirt
Clean leather with apc and da brush if necessary
Spot clean headliner
Wipedown all panels with apc/dressing mix
Clean inside glass
Final vacuum
Dress tires, wheel wells and some trim
Wax exterior via da or quick all in one via da and polish foam pad or quick all in one via rotary and foam polish pad
Clean exterior glass
Final touch ups (don't leave wax, bugs, dirt on paint, ultra wet interior, streaks on plastic in interior, dirty wheels, etc)
I've improved my time by making shortcuts and on most days I can knock out 3-4 wholesale cars a day by myself. It isn't autogeek style AT ALL but it pays the bills and is fun to do bc you don't have to worry so much about the quality. But don't get me wrong, the overall improvement of the car is still spectacular every time. Especially since the cars are usually nastier than retail cars. You get to challenge yourself The worse that can happen is they send it back to do extra stuff to it.