1. What is the maximum number of points that a player can reach for each skill?
2. Why does Primm have only a few npcs after I finished the quest My kind of town?
1. 100 in each skill. There are some derived statistics, like bonus unarmed damage, etc. that will recognize skill levels over 100, but the max most of the game recognizes is 100.
2. Depending on how you finished it, the population of the town may eventually leave the Vicky and Vance and resume their normal sandbox routines. Eventually, depending on how you finished the quest, the casino inside Vicky and Vance will reopen. http://fallout.wikia.com/wiki/My_Kind_of_Town
Now, your questions being answered, you may take into account the fact that a forum like this is dependant upon written communication. The more effective your writing skills, the more effective we can be in responding to you.
-Gunny