Can you please check the grammar in the following sentences? They are all about summer holidays.

1) During my summer holiday I got some work experience as a waitress in a guesthouse in the mountains. I just had to serve food at meals.
2) I worked full time for a month and I got very well paid. My weekly pay (wage) was (amounted to?) 600 Euro.
3) I used part of the (earned) money to travel to Germany.
My friends and I took turns to drive and we stopped (how can you express the fact that you didn't drive directly from Italy to Germany) three times, in Munchen, Berlin and Hamburg.
4) Though the journey was tiring, I had fun and time passed by very quickly.
When I was on holiday, I helped my father in his work (job)or with his work.

1. comma needed

2. comma needed; variations are fine.

3. delete (earned); "took turns driving," [<~~include the comma]; "stopped" is fine

4. comma needed; "I helped my father at his job."

1) The grammar in the first sentence is correct. However, if you would like to improve the sentence, you could consider rephrasing it to: "During my summer holiday, I gained work experience as a waitress in a guesthouse in the mountains. My role mainly involved serving food during meals."

2) The grammar in the second sentence is correct, but there are a few suggestions to improve the clarity of the sentence. You could write: "I worked full-time for a month, and I received a generous salary. My weekly wage amounted to 600 Euros."

3) The grammar in the third sentence is mostly correct. However, to clarify the sentence, you can rephrase it as: "I used part of the money I earned to travel to Germany. My friends and I took turns driving, and we made three stops, in Munich, Berlin, and Hamburg."

4) The grammar in the fourth sentence is correct. However, you can enhance the sentence by using more vivid language. For example, you could write: "Although the journey was tiring, I had a lot of fun, and time flew by quickly."

In the final sentence, both "in his work" and "with his work" are grammatically correct. However, to enhance clarity, it would be better to use "helped my father with his work."