Using idioms

★Hi Marc! It's been ages since we've met
☆Yes, last year I moved to London, so now I can only come to visit my family once in a blue moon.
★London? Wow, I would like to visit that beautiful city.
☆It's a piece of cake! (note 1) You could come with me, I'm leaving for there tomorrow, and you could stay in my home/you could stay with me/you could stay at mine.
★Oh, I don't know. Tomorrow I'm going to go to the seaside with some friends...
☆Make up your mind ! Let me know what you decide. Now it's time I call it a day: I am exausted ! See you soon.

Complimenti! I tuoi errori erano pochissimi!

Note 1: My response would be: 'What are you waiting for?/What's stopping you?' rather than 'It's a piece of cake!'

It's a piece of cake! = it's easy. e.g I don't think I'll ever learn to ride a bike...It's a piece of cake! Just keep your balance and pedal...