If your outboard
is in fine shape, there shouldn't be any reason to carry both. Carry a spare set of plugs, and a small tool kit, and you should be fine. The extra weight and space taken up will be a luxury that will be nice to have on the small boat
Your 40 watt panel should be plenty for what you've listed for charging
and whatnot. You also could do a dry run of it come spring time, hook it to a battery
, run some stuff hooked up with a temporary rig and see how you manage, that would let you know if you're going to need a second or larger one. I managed quite a bit off a 100 watt panel - VHF
, 7" chart plotter, lights, phone
and laptop charger
, and an LED TV, and never had an issue with it. That thing would put in plenty over the course of the day to recover anything that went out.
Tiller pilot could be invaluable, but it's been a long time since I've been up there, so I can't speak as to how many longer runs you'll have to benefit, but even if not for that trip, it would be great to have moving forward anyway so if it's an option, definitely go for it.
Every other suggestion has been great too. I just say don't forget a small tool kit, some books
or something to pass the time, and sunscreen.