Here is a YouTube video of this unit.
It may be possible to add an awning but I know I'd be too nervous to do it myself.
I doubt you can add a ladder. You would have to have some backing built into the walls by the manufacturer.
The unit in the video has a Thule rack on the roof.
For grey water, you'll need a portable tank. You could use a macerator pump to pump grey and black water into ta tank in the bed of the truck so you can haul it to a place to dump it.
2019 Rockwood Signature 8290BS, Reese Revolution pinbox and B&W Patriot 18K hitch
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73, w/ snow plow & camper pkgs.
2011 Rockwood Signature 8293SS (2015 - 2018)
2010 Rockwood Roo 23SS (2012 - 2014)