Can you come up with a persuasive reason to them why you can't go? School? Home stuff? Doctors appointments? Would they understand if you said you don't think you'll be well enough to travel at that time?

I know I BS reasons I can't see my mom all the time, but I feel like it's a little different when it's in the same tiny state and I do give her an hour here and there when I can handle it (or just would handle that better than being alone at the least).