[MMM]

Oh good! I was worried you were going to send a Japanese letter in romaji... that would be strange.

First I would say don't worry about it being perfect. Any effort to use Japanese will be greatly appreciated, for sure. Mistakes are OK. They understand that Japanese is hard and that you aren't a native speaker.

It's a pleasure. : よろしくお願いします　You really can't use this phrase too much.

Sumimasen, dakedo : I would probably say 悪いですけど

mata heta in desu: You mean まだ下手なんです。 That's a good phrase, and even the most skilled people at something will say it.

Boku wa chou ureshii (to) Kumamoto-ken ni ikimasu.　：　ちょう　isn't a word I would use in a letter to people I hadn't met before. I would say 熊本県に行けて、ものすごくうれしいです。

A few questions ga arimasu　：　準備とために、いくつな質問があります。

tenki wa dou desu ka de (city)??　：　Cityの天気はどうですか。

So that I know what clothing to bring.　：　持って行く洋服の事を考えております。

Is there anything for school I must bring?　：　学校のために、持って行かないとだめな物あ りませんか。

That will get you started. I bet you can answer the pet (ペット) question on your own.