My wife and I have a two year old, and we will add a newborn here in a few weeks. We cherish the memories of our trips before we had children. They were vacation type trips more than see-the-world type trips. We got about 5 trips in before we started having children, and I would give a lot to be able to have another trip like those. I definitely support taking advantage of not having children.
Your travel goals are going to influence your plans a lot, so start with solidifying those. If your goals are only to see the hot springs near your house and learn to snowboard, then you might be able to accomplish your goals using only vacation time and weekends. If you want to travel the world, then you need to start more serious planning, but there are plenty of ways to do that.
I think you need a clearer picture of the costs associated with your travel and childrearing plans, and their affect on your FIRE plans. You have plenty of financial room to buy a snowboard and ski pass, but paying for world travel could cost a lot more. If you go part time and make 50% of your salary then you'll be at $51,000 or right around your current living expenses. Your wife's potential income could give you more a cushion. A guesstimated budget for each travel scenario would help you know if your livings expenses will be more or less than they are now. Assuming you go part-time 4/2020, and then start attempting to have child in 6/2021, then you have roughly a year to travel. 500 hours of vacation could yield a lot of travel over the course of a year, but you may want to save some of those hours if your company does not have paid family leave.
You may want to work on an expected budget for when you have kids as well. Kids change pretty much everything. Also, don't forget that having children is not always a predictable event. It can happen fast or take a decade.