So I used a spreadsheet to simplify the steps, automatically track my progress, and create motivation for myself.

Step 1: make the URL.
The IDs were in column A. In column B I used a formula to concatenate them into a URL. In B2, the formula is
=concatenate("http://example.com/",a2)

Step 2: Prevent risk of losing my place.
I copied the URL from a cell, pasted it into my browser, copied the info I need, and pasted it back into the same cell.

Voila: automatic tracking.

Step 3: See how many I have left to do.
In C2 I started with the formula
=if(isnumber(find("http",b2)),c3+1,"")
Or in other words once it's copied all the way down the column: if this row still has the url then the formula would show the total number of rows remaining. Otherwise, it showed a blank cell.

Step 4: Report on what I've already accomplished
Watching the number in column C decrease wasn't really doing it for me, so I changed that formula to add a report on what I'd accomplished so far:
=IF(isnumber(find("http",B2)),C3+1,IF(isnumber(find("http",B3)),1-C3/140,""))

That gave me 0.3429 for what I'd accomplished -- I was a bit over 1/3 of the way through.

Step 5: Make it pretty
Lastly I used conditional formatting to show all cells with a value < 1 as a percentage, so 0.3429 became 34.29%, but the number of rows left still showed as plain integers. I'm kinda proud of this because I never thought of it before.

(And yes, I did finish the task)