You'll probably run into plenty of "experts" among the experts, too...
Floor heat is nice, but definitely not the best option if you're looking for the best efficiency, since it is a slow recovery system. If you were looking for efficiency and lowest cost, I would suggest looking into a mini-split heat pump to complement the gas furnace if you have off-peak available.
(Disclaimer: Not an expert either, but I have stayed at a Holiday Inn Express a few times.)
Same here. I have 3 of them. Use them in the SUV, Boat, Snowmobile, and Dual Sport bike. They seem to work better on my sled in the winter with no issues at all over my old ifinder which would eat batteries in the cold. They are discontinued but you can still find them out there on the List or bay once in a while. I like them as they are a crossover and can be used on the road or with a lake map which is the main thing I use them for. Wish they would bring something like it back.
Concrete. Way easier to plow. My parents have a gravel driveway WORST THING EVER! Impossible to snow blow because of all the rocks always wet and muddy. Sure it's cheaper but in the long it's not worth the cheaper price.
I have used a Lowrance XOG (no longer available) on my boat and on my snowmobile for years now with no problems with cold or speed of tracking. I use a Lakemaster card for Minnesota lake for fishing, a Navionics card for coverage in Canada and LOW for winter and summer fishing, and a Red Pine snowmobile trail map for riding. Have ridden at 30 below without any problem with the touchscreen, it is hooked up to sled power, so it probably is getting some heat, and I put it inside my jacket when I get off. I recommend that you do a little research on the available chips for where you are going because different manufacturers use different chips. My use pretty much limits me to Garmin, and expect to pay couple to $300+ for chips for where I travel.