Leaving a spa unsupervised this time of year in your climate for that amount of time is not wise. Your best bet would be to have a friend, family member, neighbor, etc check on your spa once or twice a week making sure it's still getting power. You might even want to consider having some premeasured doses of dichlor available for them to toss in. Regarding the temp...If it's going to be monitored by someone, turn down to 90 or so. If not, leave it be. This will 'buy' you a few more days in case you do lose power for some reason.