The chances of you getting custody are very slim. One, he is at home, and second, your job requires travel. The pot conviction will carry very little, if any weight. I guarantee you his attorney will present him as a stay at home dad. And, since you are the breadwinner, you will most likely be paying for most, if not all of his attorney fees.
Even if you got custody, the child cannot leave the state without the court's permission, which is rarely granted.
Alimony is very subjective. You would need a local attorney to find out the prevailing attitude in your area.
Have you thought about the separtion of assets, retirements, etc.? These must be split, and regardless how much or how little a person financially contributed, they are split in 1/2, or as I've seen in many cases, the person that contributes the least gets more than half.