新概念英语二中第4课有些地方不明白

新概念英语二中第4课有些地方不明白
I have just received a letter from my brother ,Tim,
He is in Australia,He has been there for six months,
Tim is an engineer ,
He is working for a big firm and he has already visited 【这里的 visited 可不可以换成 been 呢,课文听参考译文是,并且已经去过澳大利亚的不少地方了】a great number of different places in Australia .
He has just bought an Australian car and has gone to Alice Springs .a small town in the centre of Australia .【and has gone to a small town of the centre Australia ,Alice Springs,这两句话可不可这样写,为什么?】
He will soon visit Darwin 【为句话中的visit可以改为 go to 还有 soon 可以放在句尾吗】
From there,he will fly to Perth .
My brother has never been abroad before ,so he is finding this trip very exciting【这两句中的时代我完成无法理解,还有第一句中,我弟弟以前从未出过国,这句话,整篇课文都是他弟弟已经在国外了,在澳大利亚,也没有表示说他已经回国了,为什么这句话中用的是been,而不是gone呢,第二句中,因此,他觉得这次旅行非常的激动人心,为什么就变成了现在进行时呢?】