To actually answer the question is it hard to level a 5er. No, it is simple.
First is side to side level before you unhook. If the site is not level side to side you need to put some leveling blocks under one side and use the truck to pull up on to them. Next you chock the wheels which you will do anyway. You are now level side to side.
Next-Drop the landing gear to the ground.
-I always put a 2ft long 2x6 under my landing gear feet to make it easy to lever them back up into the drop tube (if this does not make sense to you yet it will once you see how landing gear work)-.
Once the sliding legs are down and locked you lift up off the hitch (which you must do anyway)using the electric up/down switch.
Then drive out from under 5er and raise or lower the front landing gear with the electric Up/down switch, to level front to back. You are now level front to back side to side.
It sounds complicated but the only part you are doing that you would not do with auto levels is putting some level blocks under the wheels IF they are needed. Which most places I go they are not needed.
The main issue with a 5er without autoleveler is setting up if there is rain---You cannot go inside and hit a button to level. Of course you have to get out in the rain to unhitch anyway or wait it out. With a motor home you can just get up and walk back to the frig for a cold one.