There are lots of variables to this.
#1 - Is there an E-night during your stay that you wanted to participate in? If so, then you at least need a UPH or a 3 day PH in order to be eligible for this event.
#2 - Do you want the ability to change to a different park during the day? If so, you would need at the least a UPH or a 3 day PH pass.
#3 - Do you intend on visiting again in the next year or two? If so, you might come out better using roughly the same amount of money that you would spend on the UPH and instead apply it toward a 4 or 5 day PH pass, so that you would have your tickets paid for the next time you visit.
#4 - Do you have any plans of actually visiting PI, DQ, WWS, or the waterparks during your stay? If not, you might find it cheaper and less wasteful to purchase simple PH tickets.
#5 - You might consider doing a simple 2nd day bounce back ticket if you are not intending to park hop or go to an E-night. It's not the cheapest option in the long term, but it works short term. And by this, I mean that PH days don't expire, so the purchase of a PH ticket with multiple days would be cheaper in the long run if you plan on another 1-5 day visit sometime in the next few years rather than paying top dollar at the prices they will be charging then for admission all over again.
I'm sure that I've missed something, but this gives you some idea of what to think about. Mickey