I beg to differ.
I recommend a plain surface without any 200-Euro design, or any other design either. These things look good to adults, but they subtract rather than add play value for children, forcing their play at least partly to follow the preset mold you have created.
Rather, give the kids a surface to play on freely and a bunch of stuff they can move around anywhere they please, such as trees, building blocks, vehicles, and animals. Provide small people and animals that can go for rides on the train. Leave the tracks de-mountable so that the children will be able to set up alternateive layouts of their own invention.
Frank Lloyd Wright became a great architect by playing with blocks, which he did all his life. Edison fooled around with a massive junk collection, and Churchill became a great strategist, starting out by playing with toy soldiers.
The ones who should be exercising their creative muscles are the kids, not the grownups.
I set up a children’s layouts at train shows around here, and they are invariably the most popular thing at the show. Parents often have to tear their kids away. Even many adults want to try them out.
My setup is devastatingly simple. I don’t have the vehicles or blocks that i recommend to you, Jose, because I have to keep it even simpler for transport, and in any case at the shows, children don’t have the time for all that, as they would at your home.
To see just how simple my setup is is you could download a couple of our club newsletters at http://www.backyardrailroaders.com/newsletter.html
Download Feb 2013 and Nov 2014, and you will find articles on my displays. Cheers!