Whatever parade attendance figure is finally released, it's sure to be wildly exaggerated. Every city does the same, every sport, every year. Just chop the announced figure in half and work downwards a bit (or a lot) to get a more realistic figure. The same applies to outdoor political rallies, protest marches, etc.
But I do expect more people than the 08 Phillies parade which was announced at 2 million and turned out to be about 850,000. The Flyers at 2.2 million in 1975 was more like 600,000.
I'll be there, probably in the LOVE park area. It will be crowded enough.
I can supply a dozen cheesesteaks to go with their whine.