Bugging in may be the best alternative you currently have, and if so having that water storage unit will be important. Ideally being able to get the rural relatives to at least humor you and allow you to ready their home for the rest of the family to relocate to would be great but with that needs to come a plan for exactly who would go there, and how you would get there if the SHTF scenario made normal travel difficult. The rural relatives would also need to understand that they are to say nothing to anyone. None of that is easy. If that is just not feasible, then a focus point should perhaps be what options you have to better secure your home, and whether any of your other relatives (grandparents etc) would be coming to your home.
In my case I am the relative living in a rural area and other than my son, the only prepper in my family. I long ago stopped talking to any of my siblings about this stuff but I do continue to try to slowly bring my daughter & her husband’s awareness along. They don’t get it, but I try a little and a little. When the time comes my son & his wife will come to my place. If possible I will try to get my daughter & her family to come (they live 850 miles from here) but the distance may just make that impossible. If others in my family see the light, I’ll take them in despite my prepping having been a source of amusement for them in the past, but I don’t plan to actively encourage them to come. They all live far away anyway. There are a few friends that I’d take in too, but again I don’t plan on encouraging anyone to come here. Until then I just keep chipping away at becoming more self sufficient.