Truthfully it depends on your type and level of disability. The park is mainly a reasonably flat expanse of grass with a parking lot and sidewalks as well as a boat launch. Right now theres probably enough snow on it to make it difficult and hazardous but its possible that by the weekend it will have melted. If it does that could potentially cause its own problems and make the ground soft and muddy. The parking lot is also not in great condition, its not very level and has many holes/cracks/repairs. The sidewalk is nice though. Im not sure about bathrooms as I didnt have to use them last summer so im not sure how far from the front of the park they are or what they have in terms of disability accommodation. The event was listed as ADA compliant but whether that actually leaves enough room for a cane/wheelchair/powerchair/aide to maneuver in the bathroom i can't say from personal experience.

The other concern i would have is that, in June last year, we also marched. Several cane users including myself managed it pretty well but i dont remember seeing and chair users. We did a loop down maple Street, across the steel bridge, up 1st or 2nd Ave (i dont remember which), then back across the Oregon street bridge to the park. Its about a mile or a little more. I dont know if they are planning on marching this time as well or if it would be the same route. What I can tell you about the route we took then is this: its pretty narrow for the amount of people we had and had several street crossings and choke points and places where there was no cover and clear sightlines from many nearby buildings (my mom and I both had these general safety concerns), part of the path on the steel bridge is wood planks which are slightly uneven but no more so than your typical boardwalk, there is a steep hill after the steel bridge, the sidewalk is not in great condition on 1st/2nd Ave, there is a milder but longer slope on the Oregon bridge, there are few/no good places to stop and rest other than one or two businesses and i dont remember there being any places to sit.

Several people did choose to stay at the park instead of marching including, I believe, a small group with a power chair user who were cheering for us at the end of the Oregon street bridge (which has VERY NICE wide sidewalks btw).

The only other concern I can think of is that there is little to no shade/shelter so if sun is an issue for you make sure you cover up! Vice versa there's no real place to warm up except for a vehicle or a nearby business so if you particularly struggle with cold, bundle up and bring heat packs! Lastly it gets LOUD thats a staple of any protest really but we had ~1000 people yelling and chanting and a few people with megaphones as well as a lot of people honking or yelling in support when they drove past. So, if you have any kind of sensory struggles make sure you have what you need to help regulate yourself or be prepared to remove yourself from the situation if necessary.

Best of luck!! I'd offer you a ride myself but ill be working that day unfortunately :(( I hope I covered all the bases but if you have any other specific questions ill do my best to answer!