Is there an autoit script I can use to designate the install folder since I don't like to install programs to the default %SYSTEMROOT%\Program Files folder?

Well an autoit script can do just about anything the problem with autoit scripts is that they are limited to a single installer (ie you can't use the same autoit script for let's say adobe acrobat 7 and office), usualy it's limited even to the version of the installer (not the same for adobe 6 and 7; just an example the autoit scripts might be compatible)

The safest bet here is to try and search for a parameter for each install for the destination folder beacause autoit scripts tend to break on a version change...

i think i didnt understand you quite well. maybe you should try to change windows default installation path to the path of your choice. so whenever you install something it will be installed to that path instead of Program Files. this way works for all setups, but im not sure if this is what you are looking for.