Not that it matters regarding the question asked, if you have glass in the windows and doors that shut I'm a bit skeptical that a 1250' house anywhere in NY has a true heat load anywhere near 62,000 BTU/hr. That's about 50 BTU per square foot of living space, a ratio rarely seen even in Fairbanks AK. Maybe an uninsulated double-wythe brick with single pane windows could come in that high. Maybe you used unrealistically high air infiltration/ventilate rate numbers or something? Most 2x4 insulated houses with storm windows and even 20 in the attic will come in at half that number or less.
For 2-zone system with 1" distribution plumbing and radiators rather than long runs of skinny-pipe baseboard plumbing it primary/secondary would very likely be overkill unless it's a high-head/low flow condensing gas boiler or something (in which case you'd want to be pumping toward the boiler, with the expansion tank at the hydraulic separator.)
I disagree heartily with nhmaster3015's comment/suggestion " Owing to the recent shortages of gas and the rising price of gas, you might also want to reconsider changing from oil." From a source-fuel BTU/$ point of view oil has not been cheaper than natural gas for over a decade. At recent years' $4/gallon New England pricing you pay about 30-35,000 BTU/$ out of oil, and 70-100,000 BTU/$ for natural gas, or 2-3x the amount of heat per dollar. (Propane would be a whole other story, and not a happy one- don't go there!)
Spot market pricing of natural gas supplied to electric utilities has been very spiky recently due to thin reserves from space heating use, but even if the residential retail price were exposed to that price volatility (which it isn't, in a regulated and contracted price market), there are no local gas mains in danger of running out. The longer term prospects for both gas and oil pricing is upward, since the cost of shale gas & oil is much higher than the old-school formations that are currently being depleted. But whereas the price of oil is determined by the world market for transportation fuel, natural gas is still pretty much a local & regional market, since the cost of liquifying and shipping that gas to a world market comes with a huge cost-adder, whereas oil is shippable in un-pressurized un-refrigerated tankers, with minimal processing required.
It's hard to come up with a scenario for the next 20 years puts heating oil at a lower price average than natural gas. As the rest of the world takes up the habit of driving, it's unlikely that the price pressure on oil will go away, even if (as isn't too likely) the US weans it's privately owned car fleet completely off of diesel and gasoline over the next 20 years. The US may have already passed it's peak oil consumption rate, but the world hasn't.
The price of heating oil would have to literally be cut in half, or the price of natural gas to more than double from current pricing to be in the same ball park as a heating fuel. And if the price of natural gas were to double, heating with ductless mini-split heat pumps would be significantly cheaper than gas, since they're roughly comparable at current regional electricity and natural gas prices. The price of electricity in the ISO/NE region rises and falls a bit with the price of natural gas, but it becoming more heavily moderated by the low marginal price of renewables (including imports from Quebec.) Even at current electricity prices the levelized cost of even grid-tied photovoltaic solar is at parity with the residential retail prices, and it's expected to drop considerably over the next 10 years rather than rising, becoming the absolute cheapest source feeding the grid. If the cost of electricity pricing jumps, so will the rate of grid tied PV installation- there's real market feedback there, and few technology or infrastructure limitations (including storage), so the long term outlook for electricity pricing is pretty good, as long as you can leverage it with heat pumps in heating applications. In a 1250' house it's highly likely that at least one large zone could be heated with a mini-split if it comes to that.