Looking to book a roundtrip flight for my girlfriend and I to the Caribbean this winter around the holidays. I've pretty much come to the following two options:

1) Use 70K UA miles for IAD-SXM in economy (at standard rate due to being before Xmas. Use 20K Avios for SXM-MIA and pay $210 total for MIA-DCA on AA.

OR

2) Use 105K UA miles for IAD-SXM-IAD/SFO. The SXM-IAD leg is via EWR so not a nonstop flight. I'd have a stopover in DC which is where I live and go to SFO for a trip in the spring with the girlfriend.

Seems to me it should be a no brainer to do #2 as it'd be nice to go somewhere else for a four night trip in the spring. I thought about using the stopover and one way flight to Europe but that'd require an extra 20K, and I'm not exactly sure when we'd get to use a week off next summer.

Avios balance is ~175K and UA balance is ~110K. I have tons of UA/UR earning capacity. Thanks.