Make sure your wife enjoys using it- pays dividends all around- and it lets her do her projects as well. Rochester, NH has some cold winters. I'd suggest a cab/heat and a plug in block heater. Good for snow removal and winter use.
I have a 30 hp and that does fine for me, Everyone always says bigger is better, but too big is less maneuverable. Get the tires filled - better traction. Avoid calcium chloride- corrodes. Beet juice/Rim guard is good. Plan on a set of chains for winter. There is always equipment for sale on craigslist - no need to rush out and buy it.
I like New Holland. Used or new- that depends on how you want to handle the cost - cash, financed, etc. Just like a car- you'll be expected to insure a financed tractor.
Read the reviews on the tractor forums on this site- a lot of info, Name brands like Deere, Kubota tend to run more expensive. Less common brands are cheaper. Chinese tractors are the cheapest - (Northern Tool, etc) and some love them, some scorn them. - Read the forums, worth it.
Many people do well with under 30 hp - depends on your needs. But look for a FEL- front end loader, and 4 wheel drive. You tube has videos of everything, Tractordata.com gives you a quick summary.
TractorData.com - information on all makes and models of tractors
HP of the tractor is different than pto shaft hp (hp running implements , tillers etc. that need power).
Good luck.