The Rose parade is second only to the Macy's parade in my mind. It delivers beautiful floats , marching bands, horses and plenty of enthusiastic crowds.
Bleacher seats are available for a price, but are hard to exit if one needs to. We usually have someone( preferably younger than yours truly) hold our place curbside. You can start marking your area about 24 hours beforehand and setting up at designated times. Check the website for specifics. A large tarp works well, lawn chairs and blankets.
The fun begins when the streets close the night before. Prior to the streets closing there is an unofficial parade of vintage autos, bicyclists and the like.
Food and coffee are available most of the night at various venues and street vendors. There are clusters of port a potties along the parade route.
Police presence is congenial and effective: not only do they remove unruly spectators they protect the all parade goers from last minute arrivals who try to worm their way into a front row spot.
Pasadena can get pretty cold at night- dress in warm clothes and bring a portable camp heater and plenty of blankets.
Everyone should attend at least once ! I confess- I live within 5 minute walk- so I feel obligated to go!