This would be right now about 65.000 Dollar.
1. Would you cash out everything?
2. Would you invest in 5 new icos with each 20 Bitcoins and hold long term (12 - 24 month) and hoping that some of that 5 icos will double your 20 Bitcoins again 10x or more times? = 500 or more Bitcoins
3. Would you invest in altcoins?
That would feel like heaven. I would do all the things you have listed. I think all three were good ways to multiply your bitcoin. Well, first, I should taste the fruit of my hard work, dedication, and perseverance. I would treat myself some food as a reward and a reminder that this is the fruit of hard work. Then for it to continue to grow and to have more income, I would invest them to good investing sites. I would just put a little part of my bitcoin to altcoins as I do not know if I would have an income like bitcoins do.