How do I Create random terrain for a 2D above view game

So I want to make the terrain so some areas are taller than others, each are is made up of blocks whose height is indicated by an instance variable (1-9) But I want all areas to be accessible so I want a block with a height of 9 for example to have at least one 8 block next to it. Any idea how I could make this work?

What i would recommend is to create a "Fake Wall" the whole terrain is the same level, but the side of a cliff would be a sprite that the player cannot pass.

Otherwise you could do a check for the block next to the player's level and see if it is equal to the current blocks's height +/- 1

Well my issue is how to make it random elevation but I figured out a way to do it more or less randomly. I create rows of empty blocks then spawn a real piece of land at a random elevation. If an empty block is next to a piece of land that block will spawn a piece of land with +/- 1 elevation