Welcome to the disABILITIES Board.
There is not a lot of information about touring WDW with visual disabilities. WDW does have braille guidebooks and audiotapes available for each park (there is a deposit that is refunded when the item is returned). We haven't really had reports of what DIS posters think of these, so I can't tell you.
The Guest Assistance Card (GAC) is just a way to give CMs some information about what you need. If you use a cane, you may not need a GAC, just one of your party to point out to the CM that you need assistance, since the cane should cue them in about what sort of assistance you need.
To request a GAC, go to Guest Services in any of the parks and explain your needs to the CM. GACs are usually good for your entire stay and you can use it for the person with a disability and up to 5 other members of their party. To use the GAC at attractions, just show it to the first CM you see. They may direct you further or just send you on in the line. Also show it to the CM at boarding (or for shows, the CM directing you to seats). For seating on rides like TOT, you shouldn't have a problem getting the front of the car seats by asking. Other rides I can think of where you would especially want the front seats would be:
Ellen's Energy Adventure in Epcot
Body Wars in Epcot
Star Tours in the Studio
For shows, you need to be aware that the wheelchair seating is often in the back, so don't just automatically follow the guests in wheelchairs. We have noticed that some CMs don't give a lot of guidance to people with visual disabilities when going into shows. For shows, there are usually several doors that open automatically when the show begins. If the CM doesn't tell you, ask which door is closest to the front row and which way you will go when you enter.
One mmore hint: For the American Adventure in Epcot, the regular entrance involves going up a very long set of steps or an escalator and then following a corridor around. The whole crowd of several thousand people are going up and trying to figure out where to go. If you want an easier (less confusing) way in, there is an elevator used to take guests with mobility problems up to the theater before the "crowd" comes up. Ask to go up in the elevator and you will be able to enter the theater a few minutes before the crowd hits.