If you can live on 47K in Oakland, which I perceive to be a high priced area, then your plan looks pretty solid. If you travel smart for a few month to different destinations, you will probably spend less unless you really like the expensive places (UK/Paris/etc.)
Two comments:
no kids, I guess? Kid expenses can alter lifestyle and finances for people.
"When traveling outside of the US, we would make use of private hospitals for any health needs and pay cash. When traveling in US, we will be enrolled in a public market health plan (estimated costs are roughly $400/mo for family with high deductible HSA PPO plan)."
Particularly if you are traveling to developing countries, you might be surprised how expensive quality private hospitals can be. It's a VERY MIXED bag. Some procedures are so well priced that a medical tourism industry develops around those procedures. But for many things, it's much more expensive than you might ever imagine.
In the motorcycle/travel subreddit, there was a guy last year who broke his leg in Inner Mongolia. He even posted a video of what looked like a fairly easy accident/nothing complicated. He went to the rural hospital, had all sorts of problems there, and then he finally got himself to Shanghai. When he got the prices in a quality private hospital in Shanghai, he flew back to Europe with his broken leg. (XX,XXX for a simple break.) Imagine if he had something complicated. These things can add up very quickly. These private hospitals in developing countries are very much hit or miss.
Personally, I would suggest one or both of the following: (1) there is evacuation insurance out there. They will do medical evacuation if you choose to have one from anywhere in the world. Med-Jet Assist. Look it up. Only $100/year and the reviews out there are good. This is what I personally have. (2) international health insurance policy. These policies have you covered everywhere except USA, which is why they are pretty cheap. About $100/month but they can be a little cheaper or more expensive. They're regular policies - not high deductable...