If I won a large jackpot such as the current MM:
1. Yes, I'd tell my family and ask them not to tell others. Since with a jackpot that large, I'd probably be giving each of 18 relatives about $200,000 to $250,000 the first year, I don't know any other way I could explain it than to tell them the full truth.
2. All of my relatives live hundreds or thousands of miles away, so they won't see what I spend on myself. I'd hire an architect to design a new home to be built elsewhere in the state, so my current friends and neighbors here wouldn't know about my lifestyle of the future. They might raise their eyebrows a bit should I decide to replace my old vehicle with a new Mercedes before I move, but I'd just say that at my age I expect that this will be the last vehicle I buy before someone takes my keys away from me, so I decided to just "go for it."
3. I don't see that I'd have need for a P.I. Though I've dealt with a local attorney, I'd attempt to get a referral to a good tax attorney in one of the large metropolitan areas of the state, with the excuse that I expect to move there. I'd prefer using an out-of-town attorney to draw up the trust or LLC through which the funds would be channeled because that might cause people to suspect that a tourist rather than a resident of this smaller community bought the winning ticket here.
4. I have no idea what I'd do about a security system. That would be something we'd have to discuss with the architect of our new home.
5. I've already been retired many years and I don't want to own many properties or much land. One new home on a large lot for under $1 million will suit me with even the largest win.
6. Legally I'm "single," but I have a significant other. We would likely marry should I win the lottery. If I didn't, I'd have to pay gift taxes on the large gifts I'd give him and that wouldn't make sense to either of us as we expect to be together "til death due us part" one way or the other. And as a married couple, it would double the amount we could gift to each relative each year without gift taxes, too. I would ask for a prenuptial agreement, but I'd want to include in it enough in wedding gift, annual gifts and the life that he would be amply provided for. In the event he predeceased me and I began dating again in my 70s or 80s, I definitely would not disclose the extent of my wealth to my dates unless or until things got serious. And I might not be as generous regarding the provisions of a prenuptial agreement with someone I hadn't known and loved before I attained such wealth.
7. What would I buy for fun? At this stage of life, I'm not big into material things or traveling the world. Been there, done that. My "fun" would be in the gifts I'd be able to give family and in the charitable donations I'd make. Most of my estate would be left to various charities, several of which are already included in my will. My relatives would get enough to make life more comfortable, but not enough to live like kings.