I agree with others that you can just wait and upgrade after you get there if you decide you want to hop. Having said that, we have always had park hoppers since there was a second park to hop to. I don't think we have ever, in all the years we have been going stayed in one park all day. My son and I (he is an adult now but we've been going since he was 3) tend to end up in Epcot every night, no matter where we start out. We've been known to start out at AK, hop over to HS and spend the afternoon then hop over to Epcot for supper or a drink. Of I may get a hankering to see the MK fireworks while we are at another park,, so we hop on over there. Or maybe we've spent the day at one park but MK has late EMH, so what the heck,, let's hop over there. We like the freedom and it makes it a whole lot easier to avoid crowds and get ADRs. We never book in advance, we go to guest services in the morning in whatever park we are at and see what's available that night. Since we are adults and have hoppers, it doesn't matter what park or if it's late in the evening.