In Westworld S01E01, Was he there just messing around being sentimental?
Had the host 'woken up' and he had gone to investigate like the response team?
The way I remember it was the response team have detected some unauthorized activity and go to investigate. I think Ford was the "unauthorized activity". I just assumed he was down there tinkering and getting ready for his big narrative.
This is speculative, but Ford likes to go down and have a (mostly) one-sided conversation with the old cowboy host (Michael Wincott, right?). Probably as a way to remind himself of what the hosts once were, crude, almost Disney level animatronic dolls.
He has several encounters with it over the season, plus he has a basic piano playing host in his office. So he seems to like to surround himself with past achievements and reminders of what the park used to be.
Given the outcome in the season 1 finale
he also wants (so he says) to set the hosts free and advance their sentience, so these old hosts may serve to drive him on. They may also be the only things he was capable of without Arnolds help, they are his personal "best" so to speak