It's especially hard with the high bow of our Donzi. I've used a two step ladder made by (I believe) Rubbermaid. Very easy to carry onboard. You can buy them from almost any hardware store. I used it before with my 27'.
I will need to find a taller ladder now that my wife is very pregnant. It's kind of a jump for her now and we'll be camping at Mead for Labor Day.