You can have your family come over as much as you want during training. The company will pay for your spouse to come over twice and kids once. Outside of that it is up to you to pay for them. You really aren't that busy during training. That is why it takes 6 months!!!
After you are online you can do your days off however you want. I usually do two long extended absences each year. Once during the summer and then once during the winter. I use my vacation with those absences and not during each month. This summer I took 48 days off and this winter will have 36 days off. During the rest of the year I will work from 20-25 days between days off. Some think that is too long but I really enjoy the longer periods off. Helps me get a lot of projects done around the house.
And UNDBadger, whoever told you you would not upgrade here if you come in as an f/o is an idiot. Many, if not most, of our captains have went through the upgrade process here as an f/o.