Is it wheel chair accessible?

Most parts, yes. Though there are a good number of stairs. It is ADA-accessible if you're willing to go out of your way a bit to assess the ramps.

I remember most parts yeas

There are elevators and ramps all throughout the river walk BUT with how bad the crowds are, it may be tough getting through people in certain spots, mainly near the mall and restaurants.

Well the river walk has stairs u would have to go through the River Center mall entry and that the elevator there also an elevator on Presa near Laundry's that will also take to the River area enjoy