HELP! Late October Honeymoon in Mexico

Hi! My fiancee and I have narrowed down our honeymoon options to Puerto Vallarta and Cancun/Riviera Maya since we want to have a good relaxing 12-14 day vacation at a really nice all-inclusive resort without breaking the bank (going over $6K). We are looking at Unico, Excellence, Secrets in Cancun and for now looking at Secrets and Iberostar in Puerto Vallarta.

Would you have any tips or recommendations to help us get more for our money? Also, what activities/excursions you recommend at either of the destinations?