This is going to be harsh but Suck. It. Up. Your spouse moved to be in DC near your family and wants one week a year with his whole family (which includes you) where his Dad lives. Is that really too much to ask?
Life isn't always fun and sometimes we make sacrifices, including of time and money, because it matters to the ones we love.
Now my opinion of course depends a bit on your husband - if he doesn't mind going solo, or having you come just for a few days, then sure, do that. But unless there's a lot more you're not saying it reads as you just have other ways you'd rather spend that time and money, and if that's the case I stay with my suck it up opinion.