I believe the walk is 0.8 miles (I don't remember where I found this, but it stuck in my head, as being the only measurement that was to the entrance, and not to the fence of the California Adventure).
This measurement was to the Marriott, which is about the same as the Hilton.
If you go out the back of the Hilton, it puts you about a full block closer.
There are a few reasonable options besides walking the full distance each day:
1) Walk by the convention center (using the path), cross Katella, go through the walkway labeled "Disney Parks", and catch the tram.
This tram is for the parking lot, but it is o.k. to ride it (I asked).
Our driver actually announced the "Katella street crossing" at one of his stops.
The tram did not seem to be operating during early entry.
I don't know if it does sometimes, and we just happened to walk though at a time it was not there.
2) Ride the bus. The bus is not great (it does not seem to benefit from Disney's expertise at logistics), but it beats walking at the end of a day that included a lot of walking.
The bus is $3 per day.
The drivers seem to get confused if you try to pay cash (although they are supposed to be able to take cash as long as one is willing to pay the full $3.00 for one ride).
Buy a bus pass at the hotel. If you do not use it until the end of the day that is o.k.
If you don't use it at all, it will not get punched, and can then be used the next day.
We actually walked the first day, but by our last day, we rode the bus.
The bus that services the Hilton, also services the Marriott. No other hotel is serviced by the E route.
Although, during less busy times, the C and E route may use the same bus.
The Bus system did not seem to anticipate the large number of people returning to the park for the fire works (after going back to the hotel).
We had to wait for the next bus.
The next bus is a 20 minute wait. They do not seem to have extra buses to call when the bus fills up.
