There is only one sure way to avoid the cable car and really enjoy Santorini:
1. Take a cruise that skips Santorini, and
2. Fly to Santorini from Athens before or after the cruise. Stay 2 or 3 nights.
The flight from Athens takes 30 minutes. There are a dozen flights to Santorini (JTR) everyday on Aegean Air. The prices start at €45 each way. There are many, many hotels in Santorini at all price points. The easiest would be to fly there the same day you fly into Athens. Just take an afternoon flight to Santorini and stay there to begin your trip. Fly back to Athens the day before your cruise or earlier if you have more time.
The few cruise excursions that avoid the cable car, and tender to and from Athinios are geared to handicapped passengers.