If you star with a female one, you start with ***muchas.*** If you start with a male one, you start with ***muchos.***

In your example we have 

>Tiene ***muchas*** playas, montañas, tiendas y restaurantes.

Since ***restaurante*** is a male word, it doesn't change the sense of the sentence.

We can do an inversion like:

> Tiene ***muchos*** restaurantes, playas, montañas, y tiendas.

But since there are more females than males, it's better to put first the ones in more quantity.

A more complex result is to have:

> Tiene ***muchas*** playas, restaurantes, montañas y tiendas.

Here you have female, male, female and female. However since the first word was used with its correct genre, the sense of the sentence doesn't change.