We've been to the Rose Parade many times. In our college days in the 60's, we took sleeping bags and sort of slept on the sidewalk. I don't know your age, but this is definitely something left for those who are young and dumb. Nowdays, many of the business owners rope off the area in front of their businesses.
I would recommend that you investigate prearranged seating. There are lots of companies which offer transport from an outlying area and reserved bleacher seating. Seeing the floats in person is an unbelievable life experience, and I would strongly encourage you to do it. It's a lot like fireworks--you have to see it in person to appreciate its magnificence. As for the "day after" when the floats are parked, many of the flowers have been picked off or fallen off, and while it is still very good, it's nothing like seeing the real thing in action.
We also worked on the CalPoly Pomona float (it's my husband's alma mater) with our kids, sorting flowers and gluing flowers and seeds. The barns where they do the work are a few miles away from the parade route, and they travel to Pasadena on the 31st. It is really cold--and if it happens to be "warm"--like in the 60's--they have refrigerated rooms you may be working in. There is great spirit, and many organizations would welcome your help. It is so satisfying to work on a float and see it go by--Cal Poly's used to always squirt water at the CalPoly spectator area--but they outlawed it a few years ago.
We are trying to rent a space at a gas station on the parade route, but there's a waiting list. The people who were there the year before get first shot. Definitely choose an RV park in one of the neighboring cities, drive your toad to the meeting area, and ride a bus in. It is a crowded, party atmosphere.
Hope you come! I know you'll be glad you did!
Linda