125K Miles: WHERE DO I GO?

1st post on the site, not sure if this is the right location...

I have 75K Ultimate Rewards, 125K Marriott points, which together can equal 125K MilagePlus...

I'm looking to go somewhere tropical/really nice weather in mid-late april or mid-june.

Are there any good star alliance/united international hubs that will have good deals on miles? Is transferring to United to best option? I'm looking to leave from any airports in NYC area (LGA, JFK, EWR)

Thanks!!!