I agree with the sentiment that the younger, the better when it comes to changing schools. I moved as a 6th grader, and it was a pretty lonely year. It wasn't until I changed schools again for middle school and everyone else was as adrift that the social situation got better.
Except maybe let him make some of the decisions about his new room? (Wall color, where the bed should be, etc.) Participation in the process always eases the road for a kid in transition, no matter what it is.
I moved houses (but not schools) between 3rd and 4th grade. It was an adventure because the property we moved into was actively under construction (acting as caretakers for the overseas owner). It was a 5 bed 3.5 bath custom house built of sandstone from an on-site quarry. It sat on 5 acres of undeveloped hillside bush country and had a 1/4 mile unpaved driveway next to a natural pond just inside the boundaries. A neighbor lived in a trailer and built custom motorcycles and had a huge, friendly dog that visited us like he was our own. Also on the property (besides the quarry and pond) were a wrecked car, a cave (wind hollowed from the sandstone hillside), a torn-down shack, and a fence on the back boundary separating us from a hoss farm.
I definitely missed my friends from the old neighborhood (although I had only lived there for about 2 years too) and it was a long way from my school friends' houses too, so it was more of a production to go to sleepovers, birthday parties, etc. On the whole though, it was a very positive experience. That was as close to an idyllic chapter in my life as I can recall. Every kid should spend some time in a semi-rural dwelling. Seeing life with rain-catch water, septic tanks, and a weekly trip to the garbage dump (the "tip") teaches all kinds of awareness about what it takes to have a modern life.