All of the WDW resorts are in compliance with the ADA laws, so you won't find any part of the CR inaccessible. The garden wing and the tower are two separate buildings, each with entry level doors that open automatically. For security reasons, at night you may have to swipe your key card (which will also be your room key) to open those doors, but in the daytime they will open automatically for you.
I'm not sure what you're asking about the elevators, but each building has its own elevators. The shops and restaurants are in the tower. If you're staying in the garden wing, it would be a short distance (5 min. or less) to the tower, through the automatic doors and straight ahead about 10 yards to the elevators, then up to the 4th floor for the shops, restaurants, and monorail (which does have its own separate elevator to the platform). When you say you should expect to wait some time, I assume you're alluding to the complaints that the tower elevators are slow? They sometimes are during busy periods, but it's mostly because so many people are using them at once. It's not all that bad and I think sometimes people are in too much of a hurry at WDW because there's so much to do. You'll be fine there.