Frankie Brimsek, The Boston Bruins' excellent goaltender from Minnesota, was one notable exception, as an all star quality goalie from the late 1930s through the early 1950s. Actually, there were usually about 8 to 10 Americans in The NHL during the 1940s. The late 1950s and early to mid 1960s were the low watermark for US born players.
Robb, from what I've read (admittedly, very little) it wasn't just US players who had to live with families "like exchange students." Wasn't that also true of Canadian kids who were not playing in their home towns?
Did kids playing juniors get any money from their teams? When you say, for example, the Rangers "sponsored" your team, what exactly did that mean? Equipment? Lastly, what were the age limits for juniors?
Absolutely true that Canadian boys playing out of town lived in "guest homes". Equipment and all team-related expenses were paid by the team, plus per-diem road living expenses. Usually we were given more than we needed, so some could be "pocketed". The Major Junior Leagues, with most of the future NHL stars, got more per diem, and so, got what amounted to a small "salary". Super players got the use of cars.
Junior A normally ranges in age from 17 through 20, but selected extremely advanced players can play at 16, IF they can make the team. The Midget level (just before Juniors, ranges from 14 through 16. 14 year olds in Midget, and 16 and many 17 year olds in Juniors, don't play a lot (mostly "sheltered minutes", but get the advantage of practising and training with the team, and working on their skills.