Dom, there are three parts to buying exactly the trailer that you want. First is patience. The second is to look at every trailer you can find and learn as much about them as you can. You'll quickly find out which trailers offer the features you're after, and what general condition you ought to expect for the age of a particular trailer, and third is to have cash in hand and be prepared to negotiate and travel for that 'perfect' trailer on a moment's notice. If you're not prepared to do that, you'll miss out on that 'perfect' trailer, and you may wait a VERY long time for the next one that suits your needs to come along!