Do you have to worry about salt spray? If so, I'd check out the salt tolerance of fruit trees.
Cherry trees are more prone to diseases than most, at least around here. (I live in the woods.)
If the pear is a Bradford or other similar non-fruiting pear, they have a poor reputation for seeding into wild areas courtesy of the birds and other critters and tend to be damaged by rough weather, so you might want to avoid that type of pear.
We have several old apple trees and one pear on my old farm, whether planted by the birds or the earlier farmers, I'm not sure. We don't spray them or prune them. We enjoy the blossoms and the critters enjoy the fruit, a nice benefit for us.

I'm not familiar with pear or cherry, but many apple trees (rosacea family) are prone to diseases that can produce ugly foliage later on in the season especially during periods of high humidity.

However, there are many cultivars that are bred to be disease-resistant. If you can find the cultivar name and do a little web surfing research on that particular cultivar, that might be wise.

Malorn,
There are many reasons why you rarely (if ever) see orchards on the Cape and Islands but I thought the article about John F Hoft might be inspiring. I will say I bought as many of his apples as I could find this fall, smaller than those from Harvard, Ma. I won't deny but oh my they were much, much, much, sweeter and crisper than any other NE apple I have ever picked...oh my I guess the gauntlet has been thrown. kt

Here is a link that might be useful: John F Hoft

Apples, cherries, and pears are all in the rose family and all are famously disease-prone.

They are truly beautiful when they bloom!

I hesitate to say much becase there are so many different kinds of apples, cherries, and pears I'm not sure what advice to offer. Knowing what the particular names are of those trees you are eyeing would help a lot.

Thanks...I will try to find out the specific names..but already..doesn't sound too promising..thanks for the Holt link...nice story..I also came across a story about the Danforth pear when I googled pear trees in MA, which makes a person think..hey no problems..but..

Thanks for all the input..

I agree with york rose. If they're cheap, why not try one of each and find out for yourself? You've got little to loose. You could always have them cut down in 5 years, when they still won't be that large. I have older pear and apple trees on my property as well. They're about 25 years, nothing's been done for the past 15. We still enjoy the blooms from the apple, but they are terribly diseased. The pears' blooms haven't been as spectacular on our trees, they're smaller, but they do produce edible fruit with no input from us, and the trees seem extremely healthy. Of course I don't know any of the varieties.