Encore has a boarding ladder we purchased from West Marine. There are two "sockets" that mount on the deck and the ladder snaps into the sockets. I bought a second pair of sockets so I could hang the ladder on either side (I don't think you could easily use it on the stern, and Encore has a bunch of stuff back there that would make it impractical even if possible. We bought the longer version (the bottom folds up when not in use) and the bottom step is in the water - convenient for boarding after a swim. The ladder includes some standoff braces to keep the steps away from the hull (gives a better foothold).
As a side note, since I have become (ahem) more elderly and rickety, I cleat a dock line on the side opposite the ladder and toss it over the boom. I wouldn't recommend using it for practicing pull-up exercises, but it does a great job of steadying me as I climb high enough to lose any kind of steadying hand hold. Dick Encore Dana Point
