My very first trip to "Disney World" was probably in the late 60s. My uncle had an orange grove outside Orlando, and we drove from Atlanta to visit him. He was considering getting out of the orange business and moving back to VA (which he did), and as we were about to leave, he told us to go see the "Disney thing" just off the highway. I don't remember if there were any signs, but the one road led up to a small windows-on-all-sides building surrounded by topiary bushes (in Disney character shapes, of course). You went in, and it was just a presentation: a diorama showing proposed development of the area, illuminated from above at the appropriate places as the soundtrack talked about each one. There were no seats... you stood and leaned against railings (like the old Circlevision 360 "ride"). I don't remember anything about the presentation (if it was the 60s, I was at most 7!), but the whole thing was cool.
On another trip, I believe WDW had just opened (or at least the park was fully built). We drove down past Orlando, but my parents kept reminding me that we were NOT going into WDW. We took that same road, and that old building was still there (I think it was the gas station), but of course the toll plaza and Disney World were just beyond it. We drove up to the toll plaza, and TURNED AROUND. Oh man, I BAWLED... I was already a Six Flags kiddo from the park in ATL, and this was like Mecca for me.

I knew they had said we weren't going in, but we were RIGHT THERE, and I could see the castle, and I felt so betrayed.
I think that original building (or one like it?) is the current Car Care Center just outside the MK.