Here is my take on an AOD swap after doing mine:
1. TV cable: AODs are particularly sensitive to TV cable adjustment, so it's best to set it up right from the start. If you're carb'd, just buy a universal carb version from Lokar or the like. This is the one NPD and others sell. I think it's like $50 or so from Lokar or Summit. I've got one, it's easy enough to setup and works fine.
2. mounting bracket: Your original C4, C6, FMX mount will not work without modification. You can buy a proper mount from lots of places. Or consider making your own like we did. Take some measurements, mock up a model, weld it up. We modeled ours after the Windsor-Fox version and it cost $35 to make including paying the welder for 40 minutes of his time.
3. Flex plate: you'll need a 164 tooth flex plate with the correct balance for your motor. Early Ford small blocks were 28 oz., later ones (like roller 5.0s) were 50 oz. You can get a new correct SFI rated flex plate from lots of places, like NPD, for less than $60.
4. Block plate. You'll want to use the AOD block plate. You can use an FMX plate, but it won't allow for proper mounting of the access/dust plate. Ask me how I know...
5. Shifter adapter: I got the Windsor-Fox version, and it was pricey at $54. I think you could probably fab up your own fairly easily for a lot less. I would if I were to do it again.
6. Starter: you'll need a starter to match the flex plate. You can probably use a starter for a '70 351W with an FMX like I did.
7. Driveshaft: you may or may not need to modify the length of your driveshaft. I didn't have to on my '70 Mach, converting from an FMX to the AOD. I've heard on earlier cars and cars with a C4, it is necessary to shorten the driveshaft an inch or 2. My respectful opinion is that you mount up the AOD and measure for the correct driveshaft length, then decide if your original will work or not.
8. Which AOD?: There is another thread running asking about this... It is best to use an AOD from either a 5.0 equipped car, or a turbo coupe or SC. If you get one from a column shift car, you'll have to flip the shifter mechanism inside the AOD. You can get it to work without doing so, but the shifter doesn't function quite right... hard to find the right gear, detents don't line up etc. Another "ask me how I know..."
I think that's it, or at least all I can think of at the moment... Hope it helps.