Some will have six or eight teams of twenty players. After several games (3-4) they pick two all star teams to play each other. Based on needs and performance in these games several will be invited back in early fall to compete for roster spots. Drafted players have slight advantage but no guarantee. USHL is the real deal. Very difficult to make teams but great opportunity if you do. Well worth the experience
No experience with NAHL process. Both great options from what I have heard.
Its worth it for the experience if that's what your looking for. USHL is primary for VERY high level players. If your kid hasn't had that kind of attention or drafted by USHL or QMJHL, what do you think the changes are he gets a roster spot? You have to use your head on this one, or you'll be sending false hope. You'll also be spending a few buckets of cash. Think it over before you pull the trigger.