Sorry but there are many things best left unsaid especially in an open internet forum. 

Probably the safest bet bank wise is looking at small home town banks and credit unions where you can walk in and actually talk to somebody in charge and keep away from the big conglomerate banks. Sure you may not have all the services and conveniences a large national chain can provide but you can also probably bet they are not making the risky and sketchy type loans that get repackaged and sold and would be less likely to get into trouble.

Other valuables it is absolutely foolish to put yourself or family at risk by putting yourself in such a dangerous situation. I would never consider that as a plan plus you have the real risk of losses due to other circumstances. 

Say somebody decides to keep it secret and bury something on their property which is a really dumb idea in the first place. They trust nobody and don't record anything about where it's at. Might be fine as long as they are around and okay. What happens if they become incapacitated, or pass away ?   Nobody knows anything about what they hid. Those left behind are now in a position where the hidden items could be most helpful for them but they don't know anything about them. There was no advantage to doing this as the items could well be lost forever or discovered as a windfall by some unrelated person many many years later.

There are professional storage options that are designed and equipped to store such items for individuals and make much more sense for all involved due to their safety. 

Probably as farmers we are in a slightly better position than the general public as you always have the ability to hold grain, livestock, hay, straw etc as a hedge against currency risks and in lieu of paper money.

It's a personal thing for everyone and what they feel is right for them and their situation. The main thing is not to do anything that puts you in a dangerous situation where you put yourself or family at risk.