I used a lightweight aluminum extension ladder for a couple years (I didn't opt for the factory installed ladder at time of purchase). As I got older, and sometimes by myself, climbing up the extension ladder (and more importantly coming down) there wasn't anyone to support the ladder and I was always getting very nervous about it slipping out from under me.
lesson learned for me, next time, make sure there's a ladder installed.
Mark, Vicki, & Scout THE dog
2015 Hemisphere 282RK
2011 2500HD Silverado
1992 Goldwing Aspencade