Anderson Leveler and Remote Level app
Personally, I find the Anderson Leveler type very easy to use, and very stable.
I have had to "roll" it onto a piece of 2x6 on occasion, and even dig a bit of a hole on the opposite wheel in extreme cases. However, I camp off the beaten path. I've never had a problem in any reasonable site.
I have a set of leveling blocks, but haven't used them since getting the Anderson … not ever. They're just too much trouble, and not as accurate.
As for one person leveling, a big level mounted on the front of the trailer, visible by the driver, works fine. I just find a spot reasonably close to level, then throw the leveler in front of the low wheel, and move ahead a few inches to level. Couldn't be easier!
However, I have recently added technology to replace the big level mounted on the front of the trailer. For Android, the free "Remote Level" app (see pictures), combined with two phones, provides a transmit/receive remote level.
I use my current phone in the cab as the receiver, and an old phone permanently mounted and powered in the trailer as the transmitter. You could also use a second active phone as the transmitter, placed temporarily on a counter when leveling.
The app can be easily calibrated for "trailer level" with the transmit phone on any surface, and stores "hitch height" for reconnecting. Units can be set to height in inches (based on trailer dimensions) for a more meaningful display.
While parking and using the Anderson Leveler, I'm only looking at side-to-side on the receiver. Once the trailer is disconnected, I have the receiver phone in hand to do the front to back level, and tweak the side to side with jacks and stabilizers.