I am not sure how to express the following sentences more naturally.
1. I went to East beach( or East coast, what is the differnce??) and swam and camped there.
2. At XX mountain, I took a cable car and ate XX in the restaurnat there.
As a Brit, but not a teacher, and using the Oxford Dictionary as my guide for the definition of "beach":
• noun a pebbly or sandy shore at the edge of the sea or a lake.
• verb bring or come on to a beach from the water. — ORIGIN perhaps related to an Old English word meaning brook.
The "East Beach" must be a pebbly or sandy shore at the edge of the sea or a lake.
The "East Coast" is an area of coastline on the East side of a landmass that may or may not have a beach (i.e. it may have high cliffs that fall directly into the water, without any significant beach).
1st sentence OK.
2nd sentence OK, apart from the spelling (restaurant)