the disney mears bus used to leave from dtd.
check it out before you go. yes, it is $14 per person rt.
if you go way early in the morning before rush hour, you can get from disney to universal by taxi for $25. i did that once.
if there are two of you, the taxi could be cheaper as long as you don't go during rush hour traffic.
i now use the town car service which is $35 for most of them.
it takes you door to door if you are switching hotels from disney to universal
if you are going for the day only, you will be dropped off near ioa then outside of city walk.