I haven't been to HSF, but I'm pretty OK as a tent camper, sometimes in pretty cool weather in the high country. It depends a whole lot on what you want, bare bones backpacking size or luxo glamping. I've done both, and in really cool weather, I don't think it matters much what tent you have, it's not going to keep you warm by itself. Theoretically a 2 person backpacking size tent with a full fly will do better than a larger tent, but the difference would be measured in only a couple of degrees.
Forgive me if I misunderstand, but I'm assuming tenting is a new adventure for you.
As the BCP resident luxo glamper, I like the room of my 4 person Big Agnes Big House 4, with the optional vestibule. It's a sturdy, quality tent, which can handle all kinds of unpleasant weather. It's not a 4 season tent by any means, but a very good 3 season tent. I like sleeping on a cot, and it comfortably holds 2 cots with plenty of room in between. I can stand almost upright in it. It's extraordinarily easy to pitch. Although it's theoretically self supporting, no tent should be erected without tying down, and I tie it down very thoroughly. My old one was damaged in a horrendous 50-60 knot wind at OSH a couple years ago; but I liked it so much that I replaced it with the latest version. Total packed weight is about 18 lbs., well within practicality for airplane camping.
https://www.bigagnes.com/Products/Produ ... filters/24Incidentally, Big Agnes is high on my list of companies which really know how to treat their customers right. When they previously repaired the poles of my old tent, their charges were really small, and their service was really quick. Because they couldn't repair my old tent this last time, they sold me the new one at a 50% discount.
With my Mr. Buddy heater, I can keep it shirt sleeve warm in freezing temps, and it has plenty of ventilation so that I don't worry about lack of oxygen. I don't sleep with the heater on, though--just use it in the evening before turning in and in the morning to make it more comfortable to get out of the warm sleeping bag. If it's rainy/snowy cold and I want to spend more time in the tent than out of it, I might run it during the day, too. By not running the heater excessively except when needed, I average about a pound of propane per 24 hour day.
For keeping warm at night, though, the only solution is a good down sleeping bag on a good thick insulating pad. There are plenty of good brands of sleeping bags--mine's a Marmot, supposedly comfortable to 20F. Although I don't put much stock in manufacturer's temperature claims, this one seems reasonably accurate. A liner helps in really cold weather, and what you wear to sleep makes a difference, too. I typically sleep in undershorts and a shirt, and socks and especially a stocking cap will make a huge difference in all night comfort when the temp gets below freezing. I always sleep on a Thermarest self-inflating pad--when I backpacked, I used a standard version about 3/4" thick, and I have a 1 1/2" thick luxo model for the big tent.
The coldest I've slept in my sleeping bag was 25F while backpacking in the Grand Gulch one winter about 10 years ago--water bottle froze inside the tent. This past June, puppy dog and I camped at Red Feather Lakes, CO, for a couple of nights--the rain turned to snow and the Big Agnes was coated with ice in the morning, so it was below freezing though not much below.
I have two 2 person backpacking size tents, a new MSR and an old brand that isn't made any longer. The old one is still plenty usable, because it was a quality tent. That's my best advice--stick with a good brand. You may get good service out of a cheapie, and people do for sure, but the biggest advantage to good brands is design details--easier to put up, easier to pack, more likely to withstand severe weather.
Cary