Looking for suggestions for a simple radiant system

Bedrooms upstairs? A,condensing combi boiler yes!

How are them floor treatments through out consistent, or wide range. Might dictate different supply water temps.

If,you like,comtrol in sleeping areas zone them that's,about it. Not a big house well I don't mean that negatively I just mean don't get zone happy. Just make sure,the smallest zone is not less than the boilers min. Modulation. Otherwise short cycling becomes an issue. Have you done a room by room heatloss first step.

House that small and tight may not even need a dedicated space heating boiler . Could do away with any short cycle issues and extra cost with a Phoenix water heater , FPHX and 2 ECM circs or as suggested above a nice combi , the kind with a small hot water tank though , not a tankless type .What is available for fuel up there ? Did you have any specific equipment in mind ?
Insulate how you want , just make sure not to create any moisture issues in the walls and pay close attention to getting air sealing proper . Are you above or below 6,000 feet , Eastern or Western side ? Basement or crawlspace ?

Is this "small place" a Get-Away place that you will use sparingly, and not be living in 24/7 in the snow times?

If so, you might consider that your radiant can be a PITA with the long periods it takes radiant to warm up the space radiantly. Like days.

Hydronic radiant is a wonderful thing. Much better in the right application. If the reason you're building this place is to enjoy cold snow activities, and you might come in from the cold, Radiant can take a long time to warm up whereas LP gas wall heaters might be a far better choice.

That may be.

When my wife is cold, she wants heat YESTERDAY. Not in a few hours.

And the cats lay in the sun for extra warmth. The dogs did too. You don't have to take a cat for walks carrying a doggie poop bag. They poop in a box. Every few days, at your convenience, take the cat litter bag out to the trash.

Rich said:

Get a new wife . Dogs are better than cats , Cats suck. Get rid of the cats , get a dog , get invisible fence , have enough property that you don't need a bag and clean the crap out of your yard every couple of days .

It took her over 51 years to train me.

Dogs aren't better than cats. Like I said. You don't have to walk a cat. I've had lots of dogs.

I live in a Condo. If you want to walk your dog in the Common Areas, you need a doggie baggie for the poop. If you take Rover to the dog park, you still a doggie baggie. No one takes Muffie the Cat to a dog park.

Invisible fence doesn't work on all dogs. It doesn't work on cats.

Its a lot quicker and easier to clean a cat box every few days that pick up doggie doo in the yard.

I'm well practiced in picking up animal waste. My wife's horse (and most horses) poop 50# pounds of horse litter per day. Not including stall bedding.

Horses, dogs and cats are far better than children. They don't get knocked up, or they don't knock others up, they don't sneak out and meet others to drink and do other things, and when you put them to bed, they stay there. And they don't steal your cars and crack them up at night when they sneak out.

With cats, if you go away, all you need is to have someone drop by occasionally and refill the cat feeder and water'er. The litter box if it is for a long time. With dogs, you have to pay to board them or have someone come a few times a day to walk them with doggie doo bags.

Once a dog learns to run through an invisible fence, you can never ever again contain them again. Like Jack Russell's.

Donner gets COLD sometimes. If you're well insulated and don't have any real mass in the emitter system other than the Warmboard, it should work OK.

15+°F is a deep setback, BTW. You may need to wake the system up before you leave the SFBA in order for it to hit its marks.