I'd have a lesson on the second day. Find your feet on the first, get used to being back not the snow and see where you're at. That way you can take better advantage of the lesson by not wasting part of it getting back into the swing of things.
That's what I'm planning anyway, I'll be on a new board this season so I'm going to ride for a few days, get used to the board and being back on the snow then get a lesson the following week. It's included with my season pass also so I might as well take advantage of it.
I also like the idea of using a lesson as an opportunity to learn a bit of a new mountain early on.