The Share a Dream Come True Parade (and likely all subsequent Disney Parades) no longer stops along the route. Guests must remain out of the path of floats at all times.
However, the Disney parades are still great!
For the Share a Dream Come True parade (MK) I would suggest showing up at Town Square at about 3pm (unless you're visiting during a peak/holiday time). Many great spots can be found on short notice.
For SpectroMagic, check out Liberty Square and Frontierland about 30-45 minutes prior to the scheduled parade time. If there are two performances, go to the second one (you should be able to show up in Liberty Sq at step-off time -about 15 minutes till it gets to Lib Sq-)
For Mickey's Jammin' Jungle Parade (DAK) check out the area near the entrance to Kilamonjaro Safaris. You'll need to arrive at least 30 minutes prior to step-off, but when the parade is over, you'll be able to walk-on to the Safari, and when you get done with that, the parade will be winding its way back into Africa (two views of a fun parade plus a great ride and you only have to wait 30 minutes for the whole thing!)
My experience with the Disney Stars and Motorcars parade is not as extensive as the other parades on property. I've seen it from Star Tours (step off), Echo Lake/Hat area (middle) and the park entry plaza (step down). There is more room in the middle of the route. Just line up behind the brass lines in the pavement.