As MakiraMarlena said, you won't be able to watch the parade from inside LTT. While the restaurant does have windows that face out onto the parade route, they have thick wavy glass in them, so you can't see anything clearly. At best, you can tell something colorful is moving by, but that's about it (I had a table near the window and you can tell there is a parade going by, but you can't really tell what the float is or anything like that).
They do not encourage/invite guests to step outside to view the parade (there is no associated viewing area). The best thing you can do is plan to finish up before the parade gets to LTT. If it's right around that time, maybe you can send all but one person out to find a viewing spot. Then the one person can pay the bill and join the rest of you afterwards. .