I love the parochial school my children attend. It is a close knit community and the friendships that we have made there extend past just playdates. During my last pregnancy, I was on bedrest. A mother in one of my kids' classroom (that I did not know well at the time) took it upon herself to organize meals being made and delivered to our home every other night. Many of the families had playdates or picked up or dropped off my kids too.
I know that my children are receiving a 'well rounded' education. In the era of 'extras' being cut from public school, my children still have p.e., art, a science lab, Spanish lessons, etc.....
I know that all the children they go to school with want their children to receive a great education. We are all there for one purpose not just because the state says children have to be in school.
I too, as a child, went to a parochial school that was in the next town, like your situation. My mother did have to make an effort to make sure that I had playdates even though she had to drive farther. I then, went to a private high school in a different town and again had to make friends. It all worked out and I don't remember being tramatized by this at all.
I then went to a state college. My dorm roommate and I were probably 'equals' in terms of how bright we were. But I had an easier time during the first year of college and I do credit it towards the great education I received before attending college.
I am also a credential teacher. I have worked in public schools for eleven years in California. You can get a good education in a public school but you do need to know your area well so you know where they are score wise. Besides test scores, check out if they teach p.e., a second language, etc.... What are the demographics of your area? What are the socio-economics of your area? In my town, if my children went to the public school they would not be with their peer group (the majority of their peer group go to private schools). But if we lived a few towns away, I would send them to a public school because it would be like a private school and the children would be from homes that value education greatly. I will never forget that when I taught Kindergarten in a public school a little girl flipped a little boy off in the classroom. Luckily, the little boy did not know what it meant but she certainly did and when I brought it up to her mother, she did not see what in the world was wrong with her daughter expressing herself this way. I was pregnant at the time with my firstborn. I remember rubbing my belly and saying, "Don't worry; you will not go to school here."
Good luck, certainly not an easy decision to make. Just educate yourself with all of your options and then go with what feels right.