All points of interest in the downtown area are between 7th street and 11th street.
At the starting coordinates find a former bank building that the Sleepover Bandits (Bruce Willis and Billy Bob Thornton) robbed in the 2001 movie "Bandits". In the parking lot of this building, look up at the back wall of the building next door where you'll see a 3 digit number. Use that for ABC.
While you're still here, look at the back wall of the old bank building and find a small red sign with the word "SPRINKLER" on it. The number of times the word "FIRE" is on that sign = D. The number of letters in the last word of that sign is = E. The checksum for A + B + C + D + E = 19
What do I mean by "checksum"? I mean if I told you X = the number of paws on a dog and Y = the number of tails on a cat and the checksum for X + Y = 5, you would know you if you'd probably gotten the right numbers for X and Y.
Leave the old bank building. There's a 4-way stop on Main Street that features a drive-thru coffee stand. On one of the corners of that 4-way stop you will find horse rings embedded in the sidewalk. You can tie your horse to one of the rings so that it doesn't wander off. The address of the doorway nearest to the horse rings is FGHI. (A "horse ring" is an iron ring cemented into the curb of the sidewalk and found at ground level next to the road. Don't waste your time counting signposts or bicycle racks).
The Clackamas County Courthouse has some historical plaques facing Main Street. One of them says that Oregon City was once known as "Willamette Falls" and it also describes a number of "firsts" for the city. How many times is the word "first" on that plaque? That number is J.
Main Street used to have an interurban trolley that went into downtown Portland. Those are gone now but there is a mural on a building between the Courthouse and the Arch Bridge that shows a picture of one. What is the 4 digit number painted on the trolley in that mural? That is KLMN.
The checksum for F + G + H + I + J + K + L + M + N = 22
In the late 1800's, Henry Weinhard had a brewery warehouse on Main Street. A doorway to the building is still flanked by cast iron stylistic images of hops, grain and kegs. The keg (circle) on the left has the numbers OPQ etched in it and the one on the right has the number RST. The checksum for this set of numbers is 26.
The very tall structure built against the rocky bluff is the only outdoor municipal elevator and vertical street in the United States. It's shown as 'Elevator Street' on the city plat. Check the operating hours before you visit. The elevator is closed on Government holidays and the operator takes a 10 minute break every 3 hours. Here is the link for it's operating hours: https://www.orcity.org/publicworks/elevator-operating-hours Walk through the tunnel at the base of the elevator. Before you get in to ride up, look to your left and you'll see a staircase with 15 steps to the first landing. How many pictures are on the walls where these 15 steps are located? That is 'U'. Ride the elevator to the top and when you step out look straight ahead to the window. Count the number of pictures mounted on the wall beneath that window. That number is 'V'.
Time to leave downtown and go to the cache, but first, pull out a map of Oregon City. Notice the streets along 7th Street that continues as it turns right and becomes Molalla Avenue. Most of the cross streets here on the hill are named for U.S. Presidents. What's odd is there is one street actually named for the loser of a Post-Depression Presidential race while the man that won the election does not have a street named for him. How many letters in the last name of the loser of that race? Call that W. The number of letters in the last name of the President without a street named for him is X. Funny thing about this presidential race, the Chicago Daily Tribune headline announced that the wrong guy had won.
The checksum for U + V + W + X = 21
The cache is here:North N N+F T C P J+I W+H West S T T Q E-B U M V-K
Best place to park:North R/T E-F D S O K D*V (That's an O as in Oscar, not a zero) West S T T U/T W X L G+I