Well, here are my two cents

First letter:
I am fine (or: Everything is fine/ wonderful), weather is great, and I even got some suntan. Yesterday, we went boating and swimming, and it was great. Later, I will send you the photos. We went to Alalin’ (?) and visited the ship where they had a great (awesome, cool) party. Today we decided to catch some sunrays, and tomorrow we will go to the Turkish bath.
Second letter:
I am fine (or: Everything is fine/wonderful). Late night tomorrow, we are going home. Today we caught some sun at the beach, and I’ve got a suntan (a pretty good suntan). We are going to have dinner/supper (dinner in American English; supper in British, I think) soon, and then we’ll have a small party. To make long story short, I am fine but I miss you.