It doesn't come with one, strangely a lot of RVs don't come with them - either they are cheap or its a liability issue. Camping World and some other places sell ladders that could be cut down if they are too tall. CW sells them as Bunk Ladders for $39.99 - probably something you could get your dealer to kick in. Both my 9/12 boys are able to get up and down without a ladder just fine - kids like to climb anyway.
2007 Winnebago Sightseer 35J
2007 Four Winns Horizon 190 Bowrider
2011 Jeep Wrangler Sahara Unlimited