For sealing roof penetrations, consider using polyurethane concrete crack filler. It sticks to anything, handles UV well and never completely hardens. Another option is to steal a page out of the marine world's handbook and use butyl tape. I have never really had great luck with silicone, caulking, RTV and that kind of thing. It works for a while then fails. If you don't want something to EVER come off and you need to seal it up really well, just mix up some 30 minute epoxy. It is sandable, paintable and can be UV stable.
For a ladder, I like the extendable/collapsable aluminum ladders and would prefer it to having something mounted to the truck, for several reasons. 'Tis a bit of a hassle to pack and unpack, when compared to something permanently mounted. There are certainly advantages and disadvantages to both.
A rip-stop nylon sheet can be laid perpendicular to the house and staked out or left to hang. When the roof packs with snow, pull the left side over the right side or vice versa = snow dumps in a matter of seconds, no shoveling required. Fans/vents could pose a problem with the tarp, but if your roof is covered in a foot of snow, I presume the same issue would be present.
If you have the cash, throw in a pair of Aussie lockers. They 'unlock' off-throttle to allow some slip whilst cornering, lock 100% under throttle and require zero maintenance. Additionally, there are no air lines or wires to run to the pumpkin.
In regards to heating, consider electric, underfloor heating mats (12VDC - 230VAC depending on output desired) from a company like Thermosoft. A thermostat can be tied to your existing system to cycle the mats off and on, maintaining a perfect 75*F temperature in your battery bank, assuming you have the heating capacity and insulation to retain the heat.
If the pneumatic cylinder does not work out for you, consider an extendable, carbon pole from a company like DragonPlate. They are lightweight, strong and impervious to road salt, mud, etc.