Writing exercise for CAE

This is an exercise i chose to make by my grammar book for CAE. I had to write a letter to a friend about an organised walking holiday that I went on. Can you tell me if i made any grammar mistakes?

Dear Martha, I enjoyed the holiday very much. The scenery was beatiful and the weather was always clear.

The walking was really tiring because I was out of training than others. So if you aren't very fit you'd better not go to this kind of holidays. We had a really knowledgeable guide, he knew a lot of informations about the places we passed through and gave us several advices to avoid risks. But they should have warned us that walking would be hard. We ate very good food, but once we have spended very much. They should have chosen a cheaper restaurant. Sometimes we lost the group because of their fast. It could have been better organised. The last hotel wasn't ready for us, we had had to wait two hours. They might have prepared the holiday in a better way, but fortunately the people were very nice and enjoyable. Thought there were a lot of things to change I recommend you the holiday because it has been a wondeful experience.

(The exercise is made to test modal forms, particularly when you say how things might have been different).

Thank you in advance for your help!

Frederick