angel275,
I am sorry to hear about your husband passing away. You are in my prayers tonight.
I am glad to hear you will keep camping/rv'ing with your Class C.
First you need to determine what kind of SunPass transponder you have. If it is about the size of your fist and attaches with suction cups to the windshield, it can be moved to your Class C and installed on its windshield. SunPass toll accounts work on the basis of you having pre-paid tolls via a credit/debit card and the Sunpass program deducts money for tolls from your account each time you roll through a toll booth. If you don't know how to access your account, go to the SunPass login link on the main page and choose the "Forgot PIN" option and see if you can find/guess the info. If not, there is a phone number in the FAQ question #2 under the "Helpful Info" link on the main page that you can call. It would help if you could get the transponder ID number off the device itself.
If you have a small chip/card with a barcode type of transponder (the mini-transponder which I have) on your windshield, it is NOT transferable and you would have to start over with a new transponder (like a mini) and new account.
You will need to reset or get your account open for you with your PIN and check the credit card info (number, expiration) and also change the vehicle type and license plate info in the account to reflect your Class C. Set the minimum amount you will let the balance fall to before you have it add more money to your account automatically in the increments you specify.
The FAQ is good to read through and the SunPass website is very helpful
https://www.sunpass.com/index . We have the mini-transponder we use to roll through the toll booths in Florida like locals.
Good luck to you and enjoy your travels.
Bama Ed
PS - if you don't have a SunPass transponder going to Disney you can simply stop and pay the tolls. However if you are planning to go further south on the Turnpike below Fort Lauderdale and Miami area as well as the Tampa-St. Pete area, those areas do NOT have toll booths and the turnpikes/toll roads rely on SunPass or something like it. So you THINK you don't need a SunPass but it comes in handy around Orlando, its airport, Tampa, or down towards West Palm Beach/Miami.