Should I take the money?

My in-laws want to pay for a trip to the Caribbean for me and my husband after I graduate nursing school this spring. I'm not sure if I should accept this gift, because it's like $1000+ dollars and I feel weird about it. We are both grown (32 & 31 yrs), and we pride ourselves on not ever asking parents for money. This gift isn't going to break their bank or anything, but my parents can't afford anything even close to this extravagant. We don't need the money and have been saving for a trip ourselves for a little while. But if I say "No thanks, its just too much.", I'm sure it will hurt their feelings. I'm not sure how to deal with this, I come from a poorer family, I've never been offered, much less had to turn down extravagant gifts. Maybe, if we take it, we could return the favor and send them on a trip. I just don't know how to manage this situation.