Roadmarks is one of Zelazny's minor novels - pleasant, but not particularly striking. While I'm not a fan of time travel stories, here Zelazny uses the time road mainly as a setting, not a plot driver, and blurs the usual problems with a little alternate, merging timelines handwaving. There's a bit of an unsupported ending as well.
The problem for Roadmarks, though, is the characters. They're nice, they're engaging, but not that much happens to them. Their obstacles are low, as is the tension. We discover minor items about Red, but - until near the end - they're not particularly compelling. Plus, confusing to me, at least, some of the characters have similar names and voices, making them harder to tell apart.
I remembered the book as of only middling interest, and anticipated liking it less, decades later. As it happens, I again found it of middling interest - not close to classics like Lord of Light, but better than Eye of Cat. In tone, it felt a bit similar to To Die in Italbar, but far less interesting, and with less character development.
If you're a fan of Zelazny already, read this for the sake of completism. If you're new to Zelazny, don't start here. You won't hate it, but if this is all you read, you may wonder why people think he's so great. He really is - in other books.