How do you say

It's been a while -- how have you been?

..in Chinese?

我们已经有一段时间没见了,你最近过得怎么样?

wǒ men yǐ jīng yǒu yī duàn shí jiān méi jiàn le , nǐ zuì jìn guò dé zěn me yàng ?

How do you say "He plans to run a marathon in three months." in Chinese?