I’m quitting my job and leaving Canada to travel for a year, starting in November. My job just offered me a promotion. Should I be open about my travel plans or just take the promotion ( and $ ) and work until I leave?

Basically the title. The extra money would really benefit me for my travel plans. I have felt this company has exploited me somewhat, offering minimal compensation for the expectation of work required. So, a part of me doesn't feel guilty. But I really don't want to burn a bridge with my manager. Can I take the position and then say I had a change of heart and that it wasn't the right timing? Advice please.