Please help with this line. そんな、踏んではいけない薄氷を渡り歩くような言い訳を連ねながら、段々と二人の空気が馴染むのを横目で見つつ、旅程を消化していたある日のこと。 I'm especially confused at the first part.. Context: He likes the same person as his very close friend and he's decided to give up his feelings for his friend's sake. Many thanks.
One day, (alternatively "that day") while reading a book, (guidebook?) I saw the two out of the corner of my eye. Their pretense was as thin as ice in summer, but over time they became friendly with each other. Yeah, not really sure what MC is doing here. Basically, he peeped at the 2 unspecified people gradually thawing over an absurd excuse he for some reason knows.
Maybe he was saying an absurd excuse to justify why he was pretending to read a book while looking at the two of the corner of his eye gradually turning themselves familiar/friendly with each other?
How about: Making such excuses, which was as if I had been walking across the thin ice that I shouldn't get in, I was quietly watching over them gradually being in a more relaxed atmosphere. And It was one of those days when I/we kept dealing with our travel schedule. I guess it is an introduction part of something important happened.
It's definitely possible. Context should definitely explain whether the 2 had some excuse they were bonding over or not. This kind of sentence is why I hate WNs. The grammar is crap. It could be read either way. I can't imagine ever seeing such a poorly written sentence in a LN, unless it is purposefully poor.
Just for your information. 横目で見る in that text is a metaphor that the speaker was peeping at them rather than staring straight. He pretended he didn't know they were going closer.
Yes, this is the most suitable one. They're indeed traveling together and this line is just before they reach a town. Thank you.