My heart goes out to you. I don't have the answers, but as the mother of 10 year-old sons, I hope that perhaps I'm able to offer some insight. Sounds like several things going on here. I can understand the feeling of wanting to "pack up" and move to a more comfortable environment, however, doing so won't mend some of the issues you mentioned.
Does your wife realize that you don't think she spends enough quality time your son? While it may be difficult to initiate a conversation with her about this, there are ways to work around this. Since your son has a lot of free time during the day (no school), could you research a few weekday options for activities in your community and then bring these ideas into a casual conversation? "Hey, I heard one of my co-workers talking about these free kids movies on Tuesday and Wednesday mornings at the local movie theate." Or are their mutual friends or neighbors who you can suggest play dates with to help foster the idea of getting your wife and son spending more quality time together?
I would encourage you to realize the reality of moving your son "Up North" right now. Where will you live? What will you do with your current home/apartment? What are your job options? What is the job market like up there? What are the schools like? Has your family encouraged you to move? Would you be able to move yet this summer so that your son can begin 5th grade in the new environment, as opposed to trying to blend in mid-semester?
You sound like a great father. I can understand that you are disappointed in your wife's lackluster participation right now, but you may be able to nudge her back into reality and involvement by focusing less on moving and more on reconnecting. I know it is unfair to be the one that needs to be the bigger, braver person to step forward and lead by example. When watching TV with your son, perhaps you can hand her the remote and ask her to find something that will appeal to all of you. If you cook the meals, try asking her if she can help your son chop up the veggies for a salad while you put the steaks on the grill. If she spends time in front of the computer, ask her to look up a recipe for a dessert you've been craving so that you can buy the ingrediants on your way home from work.
I know that moving with your son may seem like the only option right now, but I think that it is important to know that you spent a few months trying to slowly bring your wife on board for your son. In the end, if you do this and then move, you will at least know that you tried one last time to mend things. Your son will grow up seeing the effort you've put into the relationship and it will make him a better teen and better man.
Good luck. Keep posting on the forums to get others' view points.