I'm happy to report that - as is usually the case - the stretches of Greenbelt maintained by Boise or the ACHD were in excellent shape, even dry in most places. There are spots in the shade, over bridges, etc., where it's a little dicey, so it pays to be vigilant. But I made it downstream on the Boise (north) side with essentially no anxiety.
Lo and behold - I got to the bridge where you cross the river into Garden City, and it was the end of the line, at least for my brittle old bones and skinny tires.
These photos were taken maybe 50 feet and 1 minute apart...
Besides being to Boise what Shelbyville is to Springfield, Garden City has a colorful history of opposing bicycles at every opportunity. They just don't get it. They probably spend more money on "No Bicycles" signs, than they do on Greenbelt maintenance. I s'pose it was understandable when their commerce consisted mostly of RV lots, used car lots, porno stores and tattoo parlors. But nowadays they are quite proud of their new craft beer outlets and such... I'm thinking the clientele of some of those newer businesses probably ride bicycles now and then. They might choose Boise beer outlets and tattoo parlors if they perceive bike-unfriendliness in Garden City.
My hat is off to the good folks at the Boise Parks Department (who I assume do most of the Boise pathway maintenance). Not so much to our Garden City "neighbors." I expect that Boise and Garden City residents alike are appreciating the dry Boise pathways. It's nice not to have to share space with cars, when the space is also compromised by snowbanks, icy patches, frozen slush, etc.