>実際東京の私学にやるのと海外の大学に行くのでは費用はどれくらい違ってくるのでしょうか?
It's hard to say. You probably can save some portion of college money if your daughter chooses a Japanese college within a commuting range. If she decides to go to school in a foreign country, it will be much expensive because it costs both livings (room and board) and tuitions. In the US, for example, college payment ranges from $20,000-$45,000 for public/state universities. For private universities, most of them cost at least $40,000 or higher.
>最近、留学する事に興味を持ちだしているようなのですが海外に娘を一人出すというのが少し心配です。
I understand that. The first year is really challenging--new system, different language/culture environment, foods, school work etc. But once students can get the hang of it, most of them will assimilate into college life.
Many students find their life rock in a hard place for whatever reasons. I am not an exception for this. Finding some persons for help--friends, student counselors/international student office/doctors, etc., is strongly encouraged before the things get worse (i.e., depression).
>また、経験談としてどのような楽しい事がありましたか?
I graduated both Japanese college and the US college(for BA and MA). Japanese college tends to go easy on the students, while American university requires students to study a lot (term papers, exams, presentations, etc).
Getting along with American students on/off campus is really worthwhile. Hanging out with people on weekly or monthly basis is a lot of fun. I enjoy going to the church service to meet new students every Sunday morning. Sharing traditional foods and customs with local host family in special occasions--such as the Thanksgiving Day or the Christmas is very enjoyable.