Out of the limelight

　　【课文】

　　An ancient bus stopped by a dry river bed and a party of famous actors and actresses got off. Dressed in dark glasses and old clothes, they had taken special precautions so that no one should recognize them. But as they soon discovered, disguises can sometimes be too perfect.

　　'This is a wonderful place for a picnic,' said Gloria Gleam.

　　'It couldn't be better, Gloria,' Brinksley Meers agreed. 'No newspaper men, no film fans! Why don't we come more often?'

　　Meanwhile, two other actors, Rockwall Slinger and Merlin Greeves, had carried two large food baskets to a shady spot under some trees. When they had all made themselves comfortable, a stranger appeared. He looked very angry. 'Now you get out of here, all of you!' he shouted. 'I'msheriff here. Do you see that notice? It says "No Camping" -- in case you can't read!'

　　'Look, sheriff,' said Rockwall, 'don't be too hard on us. I'm Rockwall Slinger and this is Merlin Greeves.'

　　'Oh, is it?' said the sheriff with a sneer. 'Well, I'm Brinksley Meers, and my other name is Gloria Gleam. Now you get out of here fast!'

　　【课文翻译】

　　一辆古旧的汽车停在一条干涸的河床边，一群著名男女演员下了车。他们戴着墨镜，穿着旧衣裳，特别小心以防别人认出他们。但他们很快就发觉，化装的效果有时过分完美了。

　　“在这个地方野餐简直太妙了，”格格利亚.格利姆说。

　　“是再好不过的了，格格利亚。”布林克斯利.米尔斯表示同意，“没有记者，没有影迷!我们为什么不经常来这里呢?”

　　“此时，另外两位演员，罗克沃尔.斯林格和默林.格里夫斯，已经把两个大食品篮子提到了一片树荫下。当他们都已安排舒适时，一个陌生人出现了。他看上去非常气愤。“你们都从这里走开，全都走开!”他大叫着，“我是这里的司法长官。你们看到那个布告牌了吗?上面写着‘禁止野营’--除非你们不识字!”

　　“好了，好了，司法官，”罗克沃尔说，“别使我们难堪。我是罗克沃尔.斯林格，这位是默林.格里夫斯。”

　　“噢，是吗?”那位司法长官冷笑一声说道，“好，我就是布林克斯利.米尔斯。我还有一个名字叫格格利亚.格利姆。现在你们赶快滚吧!”

我的疑问1：

It couldn't be better。可以改成 Nothing could have been better. 我这边这么改可以吗？

我的疑问2：they had taken special precautions so that no one should recognize them.  像这样情态助动词用在目的状语从句中，是什么意思？这里肯定不是虚拟语气。