I forget some of you live in cities... that does make it harder to bury. but if you live near a national forest, some where back off of the trails would be a good choice... you can bury on your property I guess if you have it next to the chain link fence or other none movable metal to throw off the metal detectors.. still a risk maybe less then in some field you don't know fate of... Of course if they sell it you should have time to remove at least the stores before the bulldoze it.
About the weapons buried, good suggestions above, I can not tell what I have buried OPSEC, but they are not easly replaced....