You can also use the opposing party as something like a clock. They have their own information and motivations, and sometimes I'll schedule events in the background to happen regardless of party actions. Just roughly, but I want the PCs to feel like the other party has it's own 'life' and timeline so to speak. To make that happens I'll use timestamp type info to help give the PCs a sense of how far behind they are, and I'd also make sure there is an explicit "you just passed them and are in the lead" moment should they pull into the lead. Signed and dated notes left at key locations and mocking the PCs for being slow is fine way to get this done.