They try a second time! Liddy is back in the Howard Johnsons, but this time they tried a more direct tactic: they signed in at the main floor security desk with phony names, took the elevator two floors higher than they needed, and walked down two flights to the DNC.
Where Gonzalez was unable to pick the lock and get in.
Back to the HoJo, and Liddy realizes that they might have given away everything if the lock looked tampered with, so he repeated their plan: Liddy and two of the others went over, signed in (as Liddy tells it, "scribbled on the register"), went up to the DNC, and checked it out, finding some marks but nothing that Liddy thought would draw attention, followed by the elevator back to the main floor, and signing back out on the register.
All this happening after midnight, since the offices didn't clear out until close to then, followed by a planned midnight security sweep.
Liddy and Hunt confer at the end of the night, and Liddy insists on putting Gonzalez on a plane to Miami and back the next day, Sunday the 28th, to get the right tools.