My general advice would be to use something other than solar when camping. A panel that will charge a Macbook will be large, like the size of a card table, and you would have to carry it in a car. But if you have a car, you might as well use the cigarette lighter to charge your computer. Get a charger designed specifically to plug into the car socket. You could use an inverter to generate 115 VAC from your car, then plug in your regular wall charger, but that's much less efficient.
If you must go into the back country, consider getting an "external laptop battery." Search that term on eBay and you'll see what it is. For the weight of a solar panel, you could bring like 5 of those, although you might choose to bring only one.
Personally, my solution is to not be on the computer all the time when camping. Maybe I could check critical email with my phone, but as far as playing games - I could do that at home.