Ammarra is completely right.
Yes, the clothes Catherine wore on this trip are accessible. But they're only accessible to
people like her- Britain's (upper) Middle Class.
I believe I've said this before but the problem with Royalty, and royal houses, is that they are
obsolete*. The Queen is Head of State for a handful of countries but one of her only duties directly relating to government is approving each new Prime Minister, which is done by the Governor General (the Queen's representative) in Australia, New Zealand and Canada.
Granted, she's also the Head of the Commonwealth and in this role she will travel to Perth, Australia later this year for a Heads of Governments conference.
(FYI: What
countries are in the commonwealth? For the most part, those that were at one time or another occupied/ruled/invaded/'looked after' by Britain. India, Botswana, Cyprus and Mozambique etc. The Commonwealth functions much like the EU, in that it has a set of goals relating to, amongst other things, Democracy, free trade and World Peace)
Given the Queen rules over Constitutional Monarchies there is very little 'ruling' to do. Which is why it's so important the Royal Family is seen to be doing
something- Charities etc. When Catherine starts getting involved in such things and making a difference, well then I shall be very impressed
For the time being however- She has does a marvelous job, dressed appropriately and impressed both the public and the media. She and Will have also definitely warmed up my own perception of the RF. But it's barely been 4 months yet!
*I say obsolete because I can't think of a better word. Unnecessary? an added extra? Not sure what's right! ETA: Have just realised ADVO uses the word higher up the page to say the same thing!
)
She has just the amazing talent to make designer pieces look blah.. The last evening gown was McQueen, not in a million year would have I believed it. 
