How much money is necessary to retire for one at any earlier age or cut down to part time?
Do you think 8 million dollars is sufficient to retire at a younger age (late 30s to 40s) or work part time?
What investments would you make to preserve capital and produce sufficient dividends?
Is the market too inflated whereby stock investments will collapse to decrease capital in the future whereby cash flow is compromised in the future?
Also, would you recommend leaving medicine for a nonclinical position to limit malpractice risk in the future if money isn't in a trust?
What you are asking about is known today as The Number, or how much money you would need in the bank to stop working and still maintain your chosen lifestyle.
When your money is invested properly, a pile of money will generally have a Safe Withdrawal Rate of 4% per year, forever. Meaning, your investments will grow at (inflation + 4%), so you can withdraw 4% of your assets every year, and the dollar amount will grow with inflation so it maintains that standard of living (constant dollars) forever even after you die.
This isn't some idle theory- I worked out this math last century when the solution was less understood and the tools necessary were more difficult to access for the common investor. It was called FU money back then, e.g. enough money to be able to tell your boss or anybody else FU with minimal consequences. After figuring out the theory I worked very hard (not in medicine) to achieve the desired result, and I reached my own Number in the 1990s. I have faithfully sold 1% of my assets every quarter since then and lived off the proceeds. I've survived several recessions and other economic busts, rode out many bull markets, and I check my portfolio's performance about once every two years. I have no idea if the market is up or down right now. Yet today nearly 2 decades later I maintain the same satisfactory standard of living that I had when I quit working.
So to answer your questions in order, the amount of money you need will be highly dependent on what kind of lifestyle you will want to maintain when you quit. Everybody's Number is different. I have met a woman living satisfactorily on $6,000 a year (1990 constant dollars). I have some friends who are unhappy living on $25,000 a month and need more.
8 million 2017 dollars will throw off a lifestyle of $320,000 per year, in 2017 constant dollars, forever. Is that enough for you? Only you can answer that question. It would be enough for me, but my needs and wants are different than yours.
What kind of investments to make? The primary thing you need is low investment expenses and an appropriate asset allocation. Low expenses and good allocation will give you 95% of your desired result, and any further microadjustments are likely a waste of your time. Vanguard funds generally have the lowest expenses in the market, and Vanguard has many fund-of-funds including I'm sure a fund that meets your needs. My own needs are met by Vanguard Target Retirement 2035 fund, but your needs will be different. I prefer the Target Retirement funds because they change allocation slowly over time- your risk tolerance at age 30 will be different than your risk tolerance at age 70.
Is the market too XXX? to YYY? I don't know and I don't care and it is basically irrelevant to your preceeding questions. If you have the $8 million in cash, I would suggest buying a vanguard fund tomorrow. If you own a vanguard fund already, I would suggest keeping it there. What the market does in the next month, year, five years, or ten years is of little concern in this journey.
Finally, I have little expertise on your question about asset protection, so maybe somebody else can chime in here. I don't plan on any changes when I start practicing medicine for pay in a few months. My chosen specialty has a low rate of malpractice though, and courts often find my types of patients unsympathetic and/or unreliable.
