For those who don't have UDisc, here is a brief "written map" of the course. Holes 1-5, in theory, play counterclockwise around the southeast section of the park. Hole 1 starts east of the tennis courts or south of the baseball diamond, and plays eastward. Holes 2-4 play northward on the eastern edge of the park, near US-9. Then, walk west along Washington Ave for most of the city block to find hole 5. After hole 5, walk down to the northwest section of the park. Starting at the closest corner of that section: hole 6 plays northward, hole 7 plays southward to the west of hole 6, hole 8 plays southward to the west of hole 7, and hole 9 plays west to east along Washington Ave.
I'm feeling inspired to share this 100% true personal anecdote, but those strictly looking for course information can skip this paragraph.
The beginning of the day that would see me return to this course to properly bag it, I woke up in a Worcester, MA hotel. I spent the morning and early afternoon playing two rounds at Maple Hill (review coming soon). I then had to make my way back to Newark, NJ for a 9 PM flight home. I thought I would have time to bag another course on the way back, but traffic was so bad that my window of time started to narrow quickly. My GPS stated I would get to the airport at 6 PM, so I realized I clearly did not have time to detour, then get out of my car for an hour plus to play another 18 hole course. That was when I noticed this course - which I had visited two days prior but decided not to call "played" then due to the fact that I had only putted at the first four baskets - was only 10 minutes off of my route. Saner individuals would have continued on to the airport and not risked missing their flight if further traffic backups occurred. I knew what I had to do though.
It's weird, but I think the "seasonal" designation is the only thing stopping me from handing out a 0.0 rating for this "course". The state of the course when I played is worthy of a 0.0, but if there is some point during the year when all 9 baskets are available (and the flagged tees mentioned on UDisc are also present) it could maybe be a 1.0. So I'm being generous and averaging that out to a 0.5.
I can confidently say that I won't be returning to Nelson Park to play disc golf, even though I am likely to return to the general area in the future. I would not recommend this course to anyone except the baggiest of baggers. There is a great course at Leonard Park in Mt. Kisco - just a short drive to the east.