American flies nonstop DFW - San Jose Costa Rica. Costa Rica is warm, it's adventurous, and can be very romantic.
May is off-peak to Central America on AA, but you only have enough for one ticket if you use AA.
Wherever you decide to go, your best bet is flying on StarAlliance because you have the United and US Airways miles plus you can pad by transferring the UR points.
Once you figure out the honeymoon part (and nothing like leaving that to the last minute, eh?), do some reading on milevalue.com about how to add a free one-way. Depending on who you fly and what their rules are, you might be able to add the Medford leg on the same award ticket as the honeymoon for no / very little extra.
Anita